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2019-08-18tipc: clean up skb list lock handling on send pathJon Maloy
The policy for handling the skb list locks on the send and receive paths is simple. - On the send path we never need to grab the lock on the 'xmitq' list when the destination is an exernal node. - On the receive path we always need to grab the lock on the 'inputq' list, irrespective of source node. However, when transmitting node local messages those will eventually end up on the receive path of a local socket, meaning that the argument 'xmitq' in tipc_node_xmit() will become the 'ínputq' argument in the function tipc_sk_rcv(). This has been handled by always initializing the spinlock of the 'xmitq' list at message creation, just in case it may end up on the receive path later, and despite knowing that the lock in most cases never will be used. This approach is inaccurate and confusing, and has also concealed the fact that the stated 'no lock grabbing' policy for the send path is violated in some cases. We now clean up this by never initializing the lock at message creation, instead doing this at the moment we find that the message actually will enter the receive path. At the same time we fix the four locations where we incorrectly access the spinlock on the send/error path. This patch also reverts commit d12cffe9329f ("tipc: ensure head->lock is initialised") which has now become redundant. CC: Eric Dumazet <edumazet@google.com> Reported-by: Chris Packham <chris.packham@alliedtelesis.co.nz> Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Reviewed-by: Xin Long <lucien.xin@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-06-16tipc: purge deferredq list for each grp member in tipc_group_deleteXin Long
Syzbot reported a memleak caused by grp members' deferredq list not purged when the grp is be deleted. The issue occurs when more(msg_grp_bc_seqno(hdr), m->bc_rcv_nxt) in tipc_group_filter_msg() and the skb will stay in deferredq. So fix it by calling __skb_queue_purge for each member's deferredq in tipc_group_delete() when a tipc sk leaves the grp. Fixes: b87a5ea31c93 ("tipc: guarantee group unicast doesn't bypass group broadcast") Reported-by: syzbot+78fbe679c8ca8d264a8d@syzkaller.appspotmail.com Signed-off-by: Xin Long <lucien.xin@gmail.com> Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-04-27netlink: make nla_nest_start() add NLA_F_NESTED flagMichal Kubecek
Even if the NLA_F_NESTED flag was introduced more than 11 years ago, most netlink based interfaces (including recently added ones) are still not setting it in kernel generated messages. Without the flag, message parsers not aware of attribute semantics (e.g. wireshark dissector or libmnl's mnl_nlmsg_fprintf()) cannot recognize nested attributes and won't display the structure of their contents. Unfortunately we cannot just add the flag everywhere as there may be userspace applications which check nlattr::nla_type directly rather than through a helper masking out the flags. Therefore the patch renames nla_nest_start() to nla_nest_start_noflag() and introduces nla_nest_start() as a wrapper adding NLA_F_NESTED. The calls which add NLA_F_NESTED manually are rewritten to use nla_nest_start(). Except for changes in include/net/netlink.h, the patch was generated using this semantic patch: @@ expression E1, E2; @@ -nla_nest_start(E1, E2) +nla_nest_start_noflag(E1, E2) @@ expression E1, E2; @@ -nla_nest_start_noflag(E1, E2 | NLA_F_NESTED) +nla_nest_start(E1, E2) Signed-off-by: Michal Kubecek <mkubecek@suse.cz> Acked-by: Jiri Pirko <jiri@mellanox.com> Acked-by: David Ahern <dsahern@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-03-16net: tipc: fix a missing check of nla_nest_startKangjie Lu
nla_nest_start could fail and requires a check. The fix returns -EMSGSIZE if it fails. Signed-off-by: Kangjie Lu <kjlu@umn.edu> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-18tipc: fix info leak from kernel tipc_eventJon Maloy
We initialize a struct tipc_event allocated on the kernel stack to zero to avert info leak to user space. Reported-by: syzbot+057458894bc8cada4dee@syzkaller.appspotmail.com Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-07-21tipc: make some functions staticYueHaibing
Fixes the following sparse warnings: net/tipc/link.c:376:5: warning: symbol 'link_bc_rcv_gap' was not declared. Should it be static? net/tipc/link.c:823:6: warning: symbol 'link_prepare_wakeup' was not declared. Should it be static? net/tipc/link.c:959:6: warning: symbol 'tipc_link_advance_backlog' was not declared. Should it be static? net/tipc/link.c:1009:5: warning: symbol 'tipc_link_retrans' was not declared. Should it be static? net/tipc/monitor.c:687:5: warning: symbol '__tipc_nl_add_monitor_peer' was not declared. Should it be static? net/tipc/group.c:230:20: warning: symbol 'tipc_group_find_member' was not declared. Should it be static? Signed-off-by: YueHaibing <yuehaibing@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-07-18tipc: remove unused tipc_group_sizeYueHaibing
After commit eb929a91b213 ("tipc: improve poll() for group member socket"), it is no longer used. Signed-off-by: YueHaibing <yuehaibing@huawei.com> Acked-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-06-30tipc: extend sock diag for group communicationGhantaKrishnamurthy MohanKrishna
This commit extends the existing TIPC socket diagnostics framework for information related to TIPC group communication. Acked-by: Ying Xue <ying.xue@windriver.com> Acked-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: GhantaKrishnamurthy MohanKrishna <mohan.krishna.ghanta.krishnamurthy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-03-06Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller
All of the conflicts were cases of overlapping changes. In net/core/devlink.c, we have to make care that the resouce size_params have become a struct member rather than a pointer to such an object. Signed-off-by: David S. Miller <davem@davemloft.net>
2018-02-27tipc: correct initial value for group congestion flagJon Maloy
In commit 60c253069632 ("tipc: fix race between poll() and setsockopt()") we introduced a pointer from struct tipc_group to the 'group_is_connected' flag in struct tipc_sock, so that this field can be checked without dereferencing the group pointer of the latter struct. The initial value for this flag is correctly set to 'false' when a group is created, but we miss the case when no group is created at all, in which case the initial value should be 'true'. This has the effect that SOCK_RDM/DGRAM sockets sending datagrams never receive POLLOUT if they request so. This commit corrects this bug. Fixes: 60c253069632 ("tipc: fix race between poll() and setsockopt()") Reported-by: Hoang Le <hoang.h.le@dektek.com.au> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-02-16tipc: rename tipc_server to tipc_topsrvJon Maloy
We rename struct tipc_server to struct tipc_topsrv. This reflect its now specialized role as topology server. Accoringly, we change or add function prefixes to make it clearer which functionality those belong to. There are no functional changes in this commit. Acked-by: Ying.Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-19tipc: fix race between poll() and setsockopt()Jon Maloy
Letting tipc_poll() dereference a socket's pointer to struct tipc_group entails a race risk, as the group item may be deleted in a concurrent tipc_sk_join() or tipc_sk_leave() thread. We now move the 'open' flag in struct tipc_group to struct tipc_sock, and let the former retain only a pointer to the moved field. This will eliminate the race risk. Reported-by: syzbot+799dafde0286795858ac@syzkaller.appspotmail.com Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-09tipc: improve poll() for group member socketJon Maloy
The current criteria for returning POLLOUT from a group member socket is too simplistic. It basically returns POLLOUT as soon as the group has external destinations, something obviously leading to a lot of spinning during destination congestion situations. At the same time, the internal congestion handling is unnecessarily complex. We now change this as follows. - We introduce an 'open' flag in struct tipc_group. This flag is used only to help poll() get the setting of POLLOUT right, and *not* for congeston handling as such. This means that a user can choose to ignore an EAGAIN for a destination and go on sending messages to other destinations in the group if he wants to. - The flag is set to false every time we return EAGAIN on a send call. - The flag is set to true every time any member, i.e., not necessarily the member that caused EAGAIN, is removed from the small_win list. - We remove the group member 'usr_pending' flag. The size of the send window and presence in the 'small_win' list is sufficient criteria for recognizing congestion. This solution seems to be a reasonable compromise between 'anycast', which is normally not waiting for POLLOUT for a specific destination, and the other three send modes, which are. Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-09tipc: improve groupcast scope handlingJon Maloy
When a member joins a group, it also indicates a binding scope. This makes it possible to create both node local groups, invisible to other nodes, as well as cluster global groups, visible everywhere. In order to avoid that different members end up having permanently differing views of group size and memberhip, we must inhibit locally and globally bound members from joining the same group. We do this by using the binding scope as an additional separator between groups. I.e., a member must ignore all membership events from sockets using a different scope than itself, and all lookups for message destinations must require an exact match between the message's lookup scope and the potential target's binding scope. Apart from making it possible to create local groups using the same identity on different nodes, a side effect of this is that it now also becomes possible to create a cluster global group with the same identity across the same nodes, without interfering with the local groups. Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-09tipc: add option to suppress PUBLISH events for pre-existing publicationsJon Maloy
Currently, when a user is subscribing for binding table publications, he will receive a PUBLISH event for all already existing matching items in the binding table. However, a group socket making a subscriptions doesn't need this initial status update from the binding table, because it has already scanned it during the join operation. Worse, the multiplicatory effect of issuing mutual events for dozens or hundreds group members within a short time frame put a heavy load on the topology server, with the end result that scale out operations on a big group tend to take much longer than needed. We now add a new filter option, TIPC_SUB_NO_STATUS, for topology server subscriptions, so that this initial avalanche of events is suppressed. This change, along with the previous commit, significantly improves the range and speed of group scale out operations. We keep the new option internal for the tipc driver, at least for now. Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-09tipc: send out join messages as soon as new member is discoveredJon Maloy
When a socket is joining a group, we look up in the binding table to find if there are already other members of the group present. This is used for being able to return EAGAIN instead of EHOSTUNREACH if the user proceeds directly to a send attempt. However, the information in the binding table can be used to directly set the created member in state MBR_PUBLISHED and send a JOIN message to the peer, instead of waiting for a topology PUBLISH event to do this. When there are many members in a group, the propagation time for such events can be significant, and we can save time during the join operation if we use the initial lookup result fully. In this commit, we eliminate the member state MBR_DISCOVERED which has been the result of the initial lookup, and do instead go directly to MBR_PUBLISHED, which initiates the setup. After this change, the tipc_member FSM looks as follows: +-----------+ ---->| PUBLISHED |-----------------------------------------------+ PUB- +-----------+ LEAVE/WITHRAW | LISH |JOIN | | +-------------------------------------------+ | | | LEAVE/WITHDRAW | | | | +------------+ | | | | +----------->| PENDING |---------+ | | | | |msg/maxactv +-+---+------+ LEAVE/ | | | | | | | | WITHDRAW | | | | | | +----------+ | | | | | | | |revert/maxactv| | | | | | | V V V V V | +----------+ msg +------------+ +-----------+ +-->| JOINED |------>| ACTIVE |------>| LEAVING |---> | +----------+ +--- -+------+ LEAVE/+-----------+DOWN | A A | WITHDRAW A A A EVT | | | |RECLAIM | | | | | |REMIT V | | | | | |== adv +------------+ | | | | | +---------| RECLAIMING |--------+ | | | | +-----+------+ LEAVE/ | | | | |REMIT WITHDRAW | | | | |< adv | | | |msg/ V LEAVE/ | | | |adv==ADV_IDLE+------------+ WITHDRAW | | | +-------------| REMITTED |------------+ | | +------------+ | |PUBLISH | JOIN +-----------+ LEAVE/WITHDRAW | ---->| JOINING |-----------------------------------------------+ +-----------+ Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-09tipc: simplify group LEAVE sequenceJon Maloy
After the changes in the previous commit the group LEAVE sequence can be simplified. We now let the arrival of a LEAVE message unconditionally issue a group DOWN event to the user. When a topology WITHDRAW event is received, the member, if it still there, is set to state LEAVING, but we only issue a group DOWN event when the link to the peer node is gone, so that no LEAVE message is to be expected. Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-09tipc: create group member event messages when they are neededJon Maloy
In the current implementation, a group socket receiving topology events about other members just converts the topology event message into a group event message and stores it until it reaches the right state to issue it to the user. This complicates the code unnecessarily, and becomes impractical when we in the coming commits will need to create and issue membership events independently. In this commit, we change this so that we just notice the type and origin of the incoming topology event, and then drop the buffer. Only when it is time to actually send a group event to the user do we explicitly create a new message and send it upwards. Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-09tipc: adjustment to group member FSMJon Maloy
Analysis reveals that the member state MBR_QURANTINED in reality is unnecessary, and can be replaced by the state MBR_JOINING at all occurrencs. Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-09tipc: let group member stay in JOINED mode if unable to reclaimJon Maloy
We handle a corner case in the function tipc_group_update_rcv_win(). During extreme pessure it might happen that a message receiver has all its active senders in RECLAIMING or REMITTED mode, meaning that there is nobody to reclaim advertisements from if an additional sender tries to go active. Currently we just set the new sender to ACTIVE anyway, hence at least theoretically opening up for a receiver queue overflow by exceeding the MAX_ACTIVE limit. The correct solution to this is to instead add the member to the pending queue, while letting the oldest member in that queue revert to JOINED state. In this commit we refactor the code for handling message arrival from a JOINED member, both to make it more comprehensible and to cover the case described above. Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-09tipc: a couple of cleanupsJon Maloy
- We remove the 'reclaiming' member list in struct tipc_group, since it doesn't serve any purpose. - We simplify the GRP_REMIT_MSG branch of tipc_group_protocol_rcv(). Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-09Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller
2018-01-05tipc: simplify small window members' sorting algorithmJon Maloy
We simplify the sorting algorithm in tipc_update_member(). We also make the remaining conditional call to this function unconditional, since the same condition now is tested for inside the said function. Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-05tipc: some clarifying name changesJon Maloy
We rename some functions and variables, to make their purpose clearer. - tipc_group::congested -> tipc_group::small_win. Members in this list are not necessarily (and typically) congested. Instead, they may *potentially* be subject to congestion because their send window is less than ADV_IDLE, and therefore need to be checked during message transmission. - tipc_group_is_receiver() -> tipc_group_is_sender(). This socket will accept messages coming from members fulfilling this condition, i.e., they are senders from this member's viewpoint. - tipc_group_is_enabled() -> tipc_group_is_receiver(). Members fulfilling this condition will accept messages sent from the current socket, i.e., they are receivers from its viewpoint. There are no functional changes in this commit. Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-02tipc: fix problems with multipoint-to-point flow controlJon Maloy
In commit 04d7b574b245 ("tipc: add multipoint-to-point flow control") we introduced a protocol for preventing buffer overflow when many group members try to simultaneously send messages to the same receiving member. Stress test of this mechanism has revealed a couple of related bugs: - When the receiving member receives an advertisement REMIT message from one of the senders, it will sometimes prematurely activate a pending member and send it the remitted advertisement, although the upper limit for active senders has been reached. This leads to accumulation of illegal advertisements, and eventually to messages being dropped because of receive buffer overflow. - When the receiving member leaves REMITTED state while a received message is being read, we miss to look at the pending queue, to activate the oldest pending peer. This leads to some pending senders being starved out, and never getting the opportunity to profit from the remitted advertisement. We fix the former in the function tipc_group_proto_rcv() by returning directly from the function once it becomes clear that the remitting peer cannot leave REMITTED state at that point. We fix the latter in the function tipc_group_update_rcv_win() by looking up and activate the longest pending peer when it becomes clear that the remitting peer now can leave REMITTED state. Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-12-26tipc: fix memory leak of group member when peer node is lostJon Maloy
When a group member receives a member WITHDRAW event, this might have two reasons: either the peer member is leaving the group, or the link to the member's node has been lost. In the latter case we need to issue a DOWN event to the user right away, and let function tipc_group_filter_msg() perform delete of the member item. However, in this case we miss to change the state of the member item to MBR_LEAVING, so the member item is not deleted, and we have a memory leak. We now separate better between the four sub-cases of a WITHRAW event and make sure that each case is handled correctly. Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-12-26tipc: base group replicast ack counter on number of actual receiversJon Maloy
In commit 2f487712b893 ("tipc: guarantee that group broadcast doesn't bypass group unicast") we introduced a mechanism that requires the first (replicated) broadcast sent after a unicast to be acknowledged by all receivers before permitting sending of the next (true) broadcast. The counter for keeping track of the number of acknowledges to expect is based on the tipc_group::member_cnt variable. But this misses that some of the known members may not be ready for reception, and will never acknowledge the message, either because they haven't fully joined the group or because they are leaving the group. Such members are identified by not fulfilling the condition tested for in the function tipc_group_is_enabled(). We now set the counter for the actual number of acks to receive at the moment the message is sent, by just counting the number of recipients satisfying the tipc_group_is_enabled() test. Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-12-20tipc: remove joining group member from congested listJon Maloy
When we receive a JOIN message from a peer member, the message may contain an advertised window value ADV_IDLE that permits removing the member in question from the tipc_group::congested list. However, since the removal has been made conditional on that the advertised window is *not* ADV_IDLE, we miss this case. This has the effect that a sender sometimes may enter a state of permanent, false, broadcast congestion. We fix this by unconditinally removing the member from the congested list before calling tipc_member_update(), which might potentially sort it into the list again. Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-12-19tipc: fix list sorting bug in function tipc_group_update_member()Jon Maloy
When, during a join operation, or during message transmission, a group member needs to be added to the group's 'congested' list, we sort it into the list in ascending order, according to its current advertised window size. However, we miss the case when the member is already on that list. This will have the result that the member, after the window size has been decremented, might be at the wrong position in that list. This again may have the effect that we during broadcast and multicast transmissions miss the fact that a destination is not yet ready for reception, and we end up sending anyway. From this point on, the behavior during the remaining session is unpredictable, e.g., with underflowing window sizes. We now correct this bug by unconditionally removing the member from the list before (re-)sorting it in. Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-12-18tipc: remove leaving group member from all listsJon Maloy
A group member going into state LEAVING should never go back to any other state before it is finally deleted. However, this might happen if the socket needs to send out a RECLAIM message during this interval. Since we forget to remove the leaving member from the group's 'active' or 'pending' list, the member might be selected for reclaiming, change state to RECLAIMING, and get stuck in this state instead of being deleted. This might lead to suppression of the expected 'member down' event to the receiver. We fix this by removing the member from all lists, except the RB tree, at the moment it goes into state LEAVING. Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-12-18tipc: fix lost member events bugJon Maloy
Group messages are not supposed to be returned to sender when the destination socket disappears. This is done correctly for regular traffic messages, by setting the 'dest_droppable' bit in the header. But we forget to do that in group protocol messages. This has the effect that such messages may sometimes bounce back to the sender, be perceived as a legitimate peer message, and wreak general havoc for the rest of the session. In particular, we have seen that a member in state LEAVING may go back to state RECLAIMED or REMITTED, hence causing suppression of an otherwise expected 'member down' event to the user. We fix this by setting the 'dest_droppable' bit even in group protocol messages. Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-11-27tipc: eliminate access after delete in group_filter_msg()Jon Maloy
KASAN revealed another access after delete in group.c. This time it found that we read the header of a received message after the buffer has been released. Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-11-21tipc: fix access of released memoryJon Maloy
When the function tipc_group_filter_msg() finds that a member event indicates that the member is leaving the group, it first deletes the member instance, and then purges the message queue being handled by the call. But the message queue is an aggregated field in the just deleted item, leading the purge call to access freed memory. We fix this by swapping the order of the two actions. Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-13tipc: add multipoint-to-point flow controlJon Maloy
We already have point-to-multipoint flow control within a group. But we even need the opposite; -a scheme which can handle that potentially hundreds of sources may try to send messages to the same destination simultaneously without causing buffer overflow at the recipient. This commit adds such a mechanism. The algorithm works as follows: - When a member detects a new, joining member, it initially set its state to JOINED and advertises a minimum window to the new member. This window is chosen so that the new member can send exactly one maximum sized message, or several smaller ones, to the recipient before it must stop and wait for an additional advertisement. This minimum window ADV_IDLE is set to 65 1kB blocks. - When a member receives the first data message from a JOINED member, it changes the state of the latter to ACTIVE, and advertises a larger window ADV_ACTIVE = 12 x ADV_IDLE blocks to the sender, so it can continue sending with minimal disturbances to the data flow. - The active members are kept in a dedicated linked list. Each time a message is received from an active member, it will be moved to the tail of that list. This way, we keep a record of which members have been most (tail) and least (head) recently active. - There is a maximum number (16) of permitted simultaneous active senders per receiver. When this limit is reached, the receiver will not advertise anything immediately to a new sender, but instead put it in a PENDING state, and add it to a corresponding queue. At the same time, it will pick the least recently active member, send it an advertisement RECLAIM message, and set this member to state RECLAIMING. - The reclaimee member has to respond with a REMIT message, meaning that it goes back to a send window of ADV_IDLE, and returns its unused advertised blocks beyond that value to the reclaiming member. - When the reclaiming member receives the REMIT message, it unlinks the reclaimee from its active list, resets its state to JOINED, and notes that it is now back at ADV_IDLE advertised blocks to that member. If there are still unread data messages sent out by reclaimee before the REMIT, the member goes into an intermediate state REMITTED, where it stays until the said messages have been consumed. - The returned advertised blocks can now be re-advertised to the pending member, which is now set to state ACTIVE and added to the active member list. - To be proactive, i.e., to minimize the risk that any member will end up in the pending queue, we start reclaiming resources already when the number of active members exceeds 3/4 of the permitted maximum. Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-13tipc: guarantee delivery of last broadcast before DOWN eventJon Maloy
The following scenario is possible: - A user sends a broadcast message, and thereafter immediately leaves the group. - The LEAVE message, following a different path than the broadcast, arrives ahead of the broadcast, and the sending member is removed from the receiver's list. - The broadcast message arrives, but is dropped because the sender now is unknown to the receipient. We fix this by sequence numbering membership events, just like ordinary unicast messages. Currently, when a JOIN is sent to a peer, it contains a synchronization point, - the sequence number of the next sent broadcast, in order to give the receiver a start synchronization point. We now let even LEAVE messages contain such an "end synchronization" point, so that the recipient can delay the removal of the sending member until it knows that all messages have been received. The received synchronization points are added as sequence numbers to the generated membership events, making it possible to handle them almost the same way as regular unicasts in the receiving filter function. In particular, a DOWN event with a too high sequence number will be kept in the reordering queue until the missing broadcast(s) arrive and have been delivered. Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-13tipc: guarantee that group broadcast doesn't bypass group unicastJon Maloy
We need a mechanism guaranteeing that group unicasts sent out from a socket are not bypassed by later sent broadcasts from the same socket. We do this as follows: - Each time a unicast is sent, we set a the broadcast method for the socket to "replicast" and "mandatory". This forces the first subsequent broadcast message to follow the same network and data path as the preceding unicast to a destination, hence preventing it from overtaking the latter. - In order to make the 'same data path' statement above true, we let group unicasts pass through the multicast link input queue, instead of as previously through the unicast link input queue. - In the first broadcast following a unicast, we set a new header flag, requiring all recipients to immediately acknowledge its reception. - During the period before all the expected acknowledges are received, the socket refuses to accept any more broadcast attempts, i.e., by blocking or returning EAGAIN. This period should typically not be longer than a few microseconds. - When all acknowledges have been received, the sending socket will open up for subsequent broadcasts, this time giving the link layer freedom to itself select the best transmission method. - The forced and/or abrupt transmission method changes described above may lead to broadcasts arriving out of order to the recipients. We remedy this by introducing code that checks and if necessary re-orders such messages at the receiving end. Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-13tipc: guarantee group unicast doesn't bypass group broadcastJon Maloy
Group unicast messages don't follow the same path as broadcast messages, and there is a high risk that unicasts sent from a socket might bypass previously sent broadcasts from the same socket. We fix this by letting all unicast messages carry the sequence number of the next sent broadcast from the same node, but without updating this number at the receiver. This way, a receiver can check and if necessary re-order such messages before they are added to the socket receive buffer. Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-13tipc: introduce group multicast messagingJon Maloy
The previously introduced message transport to all group members is based on the tipc multicast service, but is logically a broadcast service within the group, and that is what we call it. We now add functionality for sending messages to all group members having a certain identity. Correspondingly, we call this feature 'group multicast'. The service is using unicast when only one destination is found, otherwise it will use the bearer broadcast service to transfer the messages. In the latter case, the receiving members filter arriving messages by looking at the intended destination instance. If there is no match, the message will be dropped, while still being considered received and read as seen by the flow control mechanism. Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-13tipc: introduce group anycast messagingJon Maloy
In this commit, we make it possible to send connectionless unicast messages to any member corresponding to the given member identity, when there is more than one such member. The sender must use a TIPC_ADDR_NAME address to achieve this effect. We also perform load balancing between the destinations, i.e., we primarily select one which has advertised sufficient send window to not cause a block/EAGAIN delay, if any. This mechanism is overlayed on the always present round-robin selection. Anycast messages are subject to the same start synchronization and flow control mechanism as group broadcast messages. Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-13tipc: introduce group unicast messagingJon Maloy
We now make it possible to send connectionless unicast messages within a communication group. To send a message, the sender can use either a direct port address, aka port identity, or an indirect port name to be looked up. This type of messages are subject to the same start synchronization and flow control mechanism as group broadcast messages. Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-13tipc: introduce flow control for group broadcast messagesJon Maloy
We introduce an end-to-end flow control mechanism for group broadcast messages. This ensures that no messages are ever lost because of destination receive buffer overflow, with minimal impact on performance. For now, the algorithm is based on the assumption that there is only one active transmitter at any moment in time. Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-13tipc: receive group membership events via member socketJon Maloy
Like with any other service, group members' availability can be subscribed for by connecting to be topology server. However, because the events arrive via a different socket than the member socket, there is a real risk that membership events my arrive out of synch with the actual JOIN/LEAVE action. I.e., it is possible to receive the first messages from a new member before the corresponding JOIN event arrives, just as it is possible to receive the last messages from a leaving member after the LEAVE event has already been received. Since each member socket is internally also subscribing for membership events, we now fix this problem by passing those events on to the user via the member socket. We leverage the already present member synch- ronization protocol to guarantee correct message/event order. An event is delivered to the user as an empty message where the two source addresses identify the new/lost member. Furthermore, we set the MSG_OOB bit in the message flags to mark it as an event. If the event is an indication about a member loss we also set the MSG_EOR bit, so it can be distinguished from a member addition event. Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-13tipc: add second source address to recvmsg()/recvfrom()Jon Maloy
With group communication, it becomes important for a message receiver to identify not only from which socket (identfied by a node:port tuple) the message was sent, but also the logical identity (type:instance) of the sending member. We fix this by adding a second instance of struct sockaddr_tipc to the source address area when a message is read. The extra address struct is filled in with data found in the received message header (type,) and in the local member representation struct (instance.) Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-13tipc: introduce communication groupsJon Maloy
As a preparation for introducing flow control for multicast and datagram messaging we need a more strictly defined framework than we have now. A socket must be able keep track of exactly how many and which other sockets it is allowed to communicate with at any moment, and keep the necessary state for those. We therefore introduce a new concept we have named Communication Group. Sockets can join a group via a new setsockopt() call TIPC_GROUP_JOIN. The call takes four parameters: 'type' serves as group identifier, 'instance' serves as an logical member identifier, and 'scope' indicates the visibility of the group (node/cluster/zone). Finally, 'flags' makes it possible to set certain properties for the member. For now, there is only one flag, indicating if the creator of the socket wants to receive a copy of broadcast or multicast messages it is sending via the socket, and if wants to be eligible as destination for its own anycasts. A group is 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. Any member of a group can send multicast ('group broadcast') messages to all group members, optionally including itself, using the primitive send(). The messages are received via the recvmsg() primitive. A socket can only be member of one group at a time. Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>