Coverity says:
*** CID 1338065: Error handling issues (CHECKED_RETURN)
/net/tipc/udp_media.c: 162 in tipc_udp_send_msg()
156 struct udp_media_addr *dst = (struct udp_media_addr *)&dest->value;
157 struct udp_media_addr *src = (struct udp_media_addr *)&b->addr.value;
158 struct sk_buff *clone;
159 struct rtable *rt;
160
161 if (skb_headroom(skb) < UDP_MIN_HEADROOM)
>>> CID 1338065: Error handling issues (CHECKED_RETURN)
>>> Calling "pskb_expand_head" without checking return value (as is done elsewhere 51 out of 56 times).
162 pskb_expand_head(skb, UDP_MIN_HEADROOM, 0, GFP_ATOMIC);
163
164 clone = skb_clone(skb, GFP_ATOMIC);
165 skb_set_inner_protocol(clone, htons(ETH_P_TIPC));
166 ub = rcu_dereference_rtnl(b->media_ptr);
167 if (!ub) {
When expanding buffer headroom over udp tunnel with pskb_expand_head(),
it's unfortunate that we don't check its return value. As a result, if
the function returns an error code due to the lack of memory, it may
cause unpredictable consequence as we unconditionally consider that
it's always successful.
Fixes: e53567948f ("tipc: conditionally expand buffer headroom over udp tunnel")
Reported-by: <scan-admin@coverity.com>
Cc: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Even if we drain receive queue thoroughly in tipc_release() after tipc
socket is removed from rhashtable, it is possible that some packets
are in flight because some CPU runs receiver and did rhashtable lookup
before we removed socket. They will achieve receive queue, but nobody
delete them at all. To avoid this leak, we register a private socket
destructor to purge receive queue, meaning releasing packets pending
on receive queue will be delayed until the last reference of tipc
socket will be released.
Signed-off-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Since commit 5266698661 ("tipc: let broadcast packet
reception use new link receive function") the broadcast send
link state was meant to always be set to LINK_ESTABLISHED, since
we don't need this link to follow the regular link FSM rules. It
was also the intention that this state anyway shouldn't impact
the run-time working state of the link, since the latter in
reality is controlled by the number of registered peers.
We have now discovered that this assumption is not quite correct.
If the broadcast link is reset because of too many retransmissions,
its state will inadvertently go to LINK_RESETTING, and never go
back to LINK_ESTABLISHED, because the LINK_FAILURE event was not
anticipated. This will work well once, but if it happens a second
time, the reset on a link in LINK_RESETTING has has no effect, and
neither the broadcast link nor the unicast links will go down as
they should.
Furthermore, it is confusing that the management tool shows that
this link is in UP state when that obviously isn't the case.
We now ensure that this state strictly follows the true working
state of the link. The state is set to LINK_ESTABLISHED when
the number of peers is non-zero, and to LINK_RESET otherwise.
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Minor overlapping changes in net/ipv4/ipmr.c, in 'net' we were
fixing the "BH-ness" of the counter bumps whilst in 'net-next'
the functions were modified to take an explicit 'net' parameter.
Signed-off-by: David S. Miller <davem@davemloft.net>
Testing of the new UDP bearer has revealed that reception of
NAME_DISTRIBUTOR, LINK_PROTOCOL/RESET and LINK_PROTOCOL/ACTIVATE
message buffers is not prepared for the case that those may be
non-linear.
We now linearize all such buffers before they are delivered up to the
generic reception layer.
In order for the commit to apply cleanly to 'net' and 'stable', we do
the change in the function tipc_udp_recv() for now. Later, we will post
a commit to 'net-next' moving the linearization to generic code, in
tipc_named_rcv() and tipc_link_proto_rcv().
Fixes: commit d0f91938be ("tipc: add ip/udp media type")
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
TO: "David S. Miller" <davem@davemloft.net>
CC: netdev@vger.kernel.org
CC: Jon Maloy <jon.maloy@ericsson.com>
CC: Ying Xue <ying.xue@windriver.com>
CC: tipc-discussion@lists.sourceforge.net
CC: linux-kernel@vger.kernel.org
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Acked-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
After the previous changes in this series, we can now remove some
unused code and structures, both in the broadcast, link aggregation
and link code.
There are no functional changes in this commit.
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Reviewed-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Correct synchronization of the broadcast link at first contact between
two nodes is dependent on the assumption that the binding table "bulk"
update passes via the same link as the initial broadcast syncronization
message, i.e., via the first link that is established.
This is not guaranteed in the current implementation. If two link
come up very close to each other in time, the "bulk" may quite well
pass via the second link, and hence void the guarantee of a correct
initial synchronization before the broadcast link is opened.
This commit makes two small changes to strengthen this guarantee.
1) We let the second established link occupy slot 1 of the
"active_links" array, while the first link will retain slot 0.
(This is in reality a cosmetic change, we could just as well keep
the current, opposite order)
2) We let the name distributor always use link selector/slot 0 when
it sends it binding table updates.
The extra traffic bias on the first link caused by this change should
be negligible, since binding table updates constitutes a very small
fraction of the total traffic.
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Reviewed-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
With the recent commit series, we have established a one-way dependency
between the link aggregation (struct tipc_node) instances and their
pertaining tipc_link instances. This has enabled quite significant code
and structure simplifications.
In this commit, we eliminate the field 'owner', which points to an
instance of struct tipc_node, from struct tipc_link, and replace it with
a pointer to struct net, which is the only external reference now needed
by a link instance.
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Reviewed-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Since all packet transmitters (link, bcast, discovery) are now sending
consumable buffer clones to the bearer layer, we can remove the
redundant buffer cloning that is perfomed in the lower level functions
tipc_l2_send_msg() and tipc_udp_send_msg().
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Reviewed-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The neighbor discovery function currently uses the function
tipc_bearer_send() for transmitting packets, assuming that the
sent buffers are not consumed by the called function.
We want to change this, in order to avoid unnecessary buffer cloning
elswhere in the code.
This commit introduces a new function tipc_bearer_skb() which consumes
the sent buffers, and let the discoverer functions use this new call
instead. The discoverer does now itself perform the cloning when
that is necessary.
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Reviewed-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Until now, we have only been supporting a fix MTU size of 1500 bytes
for all broadcast media, irrespective of their actual capability.
We now make the broadcast MTU adaptable to the carrying media, i.e.,
we use the smallest MTU supported by any of the interfaces attached
to TIPC.
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Reviewed-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Until now, we have been keeping track of the exact set of broadcast
destinations though the help structure tipc_node_map. This leads us to
have to maintain a whole infrastructure for supporting this, including
a pseudo-bearer and a number of functions to manipulate both the bearers
and the node map correctly. Apart from the complexity, this approach is
also limiting, as struct tipc_node_map only can support cluster local
broadcast if we want to avoid it becoming excessively large. We want to
eliminate this limitation, in order to enable introduction of scoped
multicast in the future.
A closer analysis reveals that it is unnecessary maintaining this "full
set" overview; it is sufficient to keep a counter per bearer, indicating
how many nodes can be reached via this bearer at the moment. The protocol
is now robust enough to handle transitional discrepancies between the
nominal number of reachable destinations, as expected by the broadcast
protocol itself, and the number which is actually reachable at the
moment. The initial broadcast synchronization, in conjunction with the
retransmission mechanism, ensures that all packets will eventually be
acknowledged by the correct set of destinations.
This commit introduces these changes.
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Reviewed-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The code path for receiving broadcast packets is currently distinct
from the unicast path. This leads to unnecessary code and data
duplication, something that can be avoided with some effort.
We now introduce separate per-peer tipc_link instances for handling
broadcast packet reception. Each receive link keeps a pointer to the
common, single, broadcast link instance, and can hence handle release
and retransmission of send buffers as if they belonged to the own
instance.
Furthermore, we let each unicast link instance keep a reference to both
the pertaining broadcast receive link, and to the common send link.
This makes it possible for the unicast links to easily access data for
broadcast link synchronization, as well as for carrying acknowledges for
received broadcast packets.
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Reviewed-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Until now, we have tried to support both the newer, dedicated broadcast
synchronization mechanism along with the older, less safe, RESET_MSG/
ACTIVATE_MSG based one. The latter method has turned out to be a hazard
in a highly dynamic cluster, so we find it safer to disable it completely
when we find that the former mechanism is supported by the peer node.
For this purpose, we now introduce a new capabability bit,
TIPC_BCAST_SYNCH, to inform any peer nodes that dedicated broadcast
syncronization is supported by the present node. The new bit is conveyed
between peers in the 'capabilities' field of neighbor discovery messages.
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Reviewed-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit simplifies the broadcast link transmission function, by
leveraging previous changes to the link transmission function and the
broadcast transmission link life cycle.
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Reviewed-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Realizing that unicast is just a special case of broadcast, we also see
that we can go in the other direction, i.e., that modest changes to the
current unicast link can make it generic enough to support broadcast.
The following changes are introduced here:
- A new counter ("ackers") in struct tipc_link, to indicate how many
peers need to ack a packet before it can be released.
- A corresponding counter in the skb user area, to keep track of how
many peers a are left to ack before a buffer can be released.
- A new counter ("acked"), to keep persistent track of how far a peer
has acked at the moment, i.e., where in the transmission queue to
start updating buffers when the next ack arrives. This is to avoid
double acknowledgements from a peer, with inadvertent relase of
packets as a result.
- A more generic tipc_link_retrans() function, where retransmit starts
from a given sequence number, instead of the first packet in the
transmision queue. This is to minimize the number of retransmitted
packets on the broadcast media.
When the new functionality is taken into use in the next commits,
we expect it to have minimal effect on unicast mode performance.
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Reviewed-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The broadcast link instance (struct tipc_link) used for sending is
currently aggregated into struct tipc_bclink. This means that we cannot
use the regular tipc_link_create() function for initiating the link, but
do instead have to initiate numerous fields directly from the
bcast_init() function.
We want to reduce dependencies between the broadcast functionality
and the inner workings of tipc_link. In this commit, we introduce
a new function tipc_bclink_create() to link.c, and allocate the
instance of the link separately using this function.
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Reviewed-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In reality, the link implementation is already independent from
struct tipc_bearer, in that it doesn't store any reference to it.
However, we still pass on a pointer to a bearer instance in the
function tipc_link_create(), just to have it extract some
initialization information from it.
I later commits, we need to create instances of tipc_link without
having any associated struct tipc_bearer. To facilitate this, we
want to extract the initialization data already in the creator
function in node.c, before calling tipc_link_create(), and pass
this info on as individual parameters in the call.
This commit introduces this change.
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Reviewed-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The broadcast transmission link is currently instantiated when the
network subsystem is started, i.e., on order from user space via netlink.
This forces the broadcast transmission code to do unnecessary tests for
the existence of the transmission link, as well in single mode node as
in network mode.
In this commit, we do instead create the link during initialization of
the name space, and remove it when it is stopped. The fact that the
transmission link now has a guaranteed longer life cycle than any of its
potential clients paves the way for further code simplifcations
and optimizations.
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Reviewed-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The broadcast lock will need to be acquired outside bcast.c in a later
commit. For this reason, we move the lock to struct tipc_net. Consistent
with the changes in the previous commit, we also introducee two new
functions tipc_bcast_lock() and tipc_bcast_unlock(). The code that is
currently using tipc_bclink_lock()/unlock() will be phased out during
the coming commits in this series.
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Reviewed-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently, a number of structure and function definitions related
to the broadcast functionality are unnecessarily exposed in the file
bcast.h. This obscures the fact that the external interface towards
the broadcast link in fact is very narrow, and causes unnecessary
recompilations of other files when anything changes in those
definitions.
In this commit, we move as many of those definitions as is currently
possible to the file bcast.c.
We also rename the structure 'tipc_bclink' to 'tipc_bc_base', both
since the name does not correctly describe the contents of this
struct, and will do so even less in the future, and because we want
to use the term 'link' more appropriately in the functionality
introduced later in this series.
Finally, we rename a couple of functions, such as tipc_bclink_xmit()
and others that will be kept in the future, to include the term 'bcast'
instead.
There are no functional changes in this commit.
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Reviewed-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Conflicts:
net/ipv6/xfrm6_output.c
net/openvswitch/flow_netlink.c
net/openvswitch/vport-gre.c
net/openvswitch/vport-vxlan.c
net/openvswitch/vport.c
net/openvswitch/vport.h
The openvswitch conflicts were overlapping changes. One was
the egress tunnel info fix in 'net' and the other was the
vport ->send() op simplification in 'net-next'.
The xfrm6_output.c conflicts was also a simplification
overlapping a bug fix.
Signed-off-by: David S. Miller <davem@davemloft.net>
In commit d999297c3d ("tipc: reduce locking scope during packet reception")
we altered the packet retransmission function. Since then, when
restransmitting packets, we create a clone of the original buffer
using __pskb_copy(skb, MIN_H_SIZE), where MIN_H_SIZE is the size of
the area we want to have copied, but also the smallest possible TIPC
packet size. The value of MIN_H_SIZE is 24.
Unfortunately, __pskb_copy() also has the effect that the headroom
of the cloned buffer takes the size MIN_H_SIZE. This is too small
for carrying the packet over the UDP tunnel bearer, which requires
a minimum headroom of 28 bytes. A change to just use pskb_copy()
lets the clone inherit the original headroom of 80 bytes, but also
assumes that the copied data area is of at least that size, something
that is not always the case. So that is not a viable solution.
We now fix this by adding a check for sufficient headroom in the
transmit function of udp_media.c, and expanding it when necessary.
Fixes: commit d999297c3d ("tipc: reduce locking scope during packet reception")
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The current code for message reassembly is erroneously assuming that
the the first arriving fragment buffer always is linear, and then goes
ahead resetting the fragment list of that buffer in anticipation of
more arriving fragments.
However, if the buffer already happens to be non-linear, we will
inadvertently drop the already attached fragment list, and later
on trig a BUG() in __pskb_pull_tail().
We see this happen when running fragmented TIPC multicast across UDP,
something made possible since
commit d0f91938be ("tipc: add ip/udp media type")
We fix this by not resetting the fragment list when the buffer is non-
linear, and by initiatlizing our private fragment list tail pointer to
the tail of the existing fragment list.
Fixes: commit d0f91938be ("tipc: add ip/udp media type")
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The default fix broadcast window size is currently set to 20 packets.
This is a very low value, set at a time when we were still testing on
10 Mb/s hubs, and a change to it is long overdue.
Commit 7845989cb4 ("net: tipc: fix stall during bclink wakeup procedure")
revealed a problem with this low value. For messages of importance LOW,
the backlog queue limit will be calculated to 30 packets, while a
single, maximum sized message of 66000 bytes, carried across a 1500 MTU
network consists of 46 packets.
This leads to the following scenario (among others leading to the same
situation):
1: Msg 1 of 46 packets is sent. 20 packets go to the transmit queue, 26
packets to the backlog queue.
2: Msg 2 of 46 packets is attempted sent, but rejected because there is
no more space in the backlog queue at this level. The sender is added
to the wakeup queue with a "pending packets chain size" number of 46.
3: Some packets in the transmit queue are acked and released. We try to
wake up the sender, but the pending size of 46 is bigger than the LOW
wakeup limit of 30, so this doesn't happen.
5: Subsequent acks releases all the remaining buffers. Each time we test
for the wakeup criteria and find that 46 still is larger than 30,
even after both the transmit and the backlog queues are empty.
6: The sender is never woken up and given a chance to send its message.
He is stuck.
We could now loosen the wakeup criteria (used by link_prepare_wakeup())
to become equal to the send criteria (used by tipc_link_xmit()), i.e.,
by ignoring the "pending packets chain size" value altogether, or we can
just increase the queue limits so that the criteria can be satisfied
anyway. There are good reasons (potentially multiple waiting senders) to
not opt for the former solution, so we choose the latter one.
This commit fixes the problem by giving the broadcast link window a
default value of 50 packets. We also introduce a new minimum link
window size BCLINK_MIN_WIN of 32, which is enough to always avoid the
described situation. Finally, in order to not break any existing users
which may set the window explicitly, we enforce that the window is set
to the new minimum value in case the user is trying to set it to
anything lower.
Fixes: 7845989cb4 ("net: tipc: fix stall during bclink wakeup procedure")
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Reviewed-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Conflicts:
drivers/net/usb/asix_common.c
net/ipv4/inet_connection_sock.c
net/switchdev/switchdev.c
In the inet_connection_sock.c case the request socket hashing scheme
is completely different in net-next.
The other two conflicts were overlapping changes.
Signed-off-by: David S. Miller <davem@davemloft.net>
The change made in the previous commit revealed a small flaw in the way
the node FSM is updated. When the function tipc_node_link_down() is
called for the last link to a node, we should check whether this was
caused by a local reset or by a received RESET message from the peer.
In the latter case, we can directly issue a PEER_LOST_CONTACT_EVT to
the node FSM, so that it is ready to re-establish contact. If this is
not done, the peer node will sometimes have to go through a second
establish cycle before the link becomes stable.
We fix this in this commit by conditionally issuing the mentioned
event in the function tipc_node_link_down(). We also move LINK_RESET
FSM even away from the link_reset() function and into the caller
function, partially because it is easier to follow the code when state
changes are gathered at a limited number of locations, partially
because there will be cases in future commits where we don't want the
link to go RESET mode when link_reset() is called.
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>
When a link is taken down because of a node local event, such as
disabling of a bearer or an interface, we currently leave it to the
peer node to discover the broken communication. The default time for
such failure discovery is 1.5-2 seconds.
If we instead allow the terminating link endpoint to send out a RESET
message at the moment it is reset, we can achieve the impression that
both endpoints are going down instantly. Since this is a very common
scenario, we find it worthwhile to make this small modification.
Apart from letting the link produce the said message, we also have to
ensure that the interface is able to transmit it before TIPC is
detached. We do this by performing the disabling of a bearer in three
steps:
1) Disable reception of TIPC packets from the interface in question.
2) Take down the links, while allowing them so send out a RESET message.
3) Disable transmission of TIPC packets on the interface.
Apart from this, we now have to react on the NETDEV_GOING_DOWN event,
instead of as currently the NEDEV_DOWN event, to ensure that such
transmission is possible during the teardown phase.
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>
Link establishing, just like link teardown, is a non-atomic action, in
the sense that discovering that conditions are right to establish a link,
and the actual adding of the link to one of the node's send slots is done
in two different lock contexts. The link FSM is designed to help bridging
the gap between the two contexts in a safe manner.
We have now discovered a weakness in the implementaton of this FSM.
Because we directly let the link go from state LINK_ESTABLISHING to
state LINK_ESTABLISHED already in the first lock context, we are unable
to distinguish between a fully established link, i.e., a link that has
been added to its slot, and a link that has not yet reached the second
lock context. It may hence happen that a manual intervention, e.g., when
disabling an interface, causes the function tipc_node_link_down() to try
removing the link from the node slots, decrementing its active link
counter etc, although the link was never added there in the first place.
We solve this by delaying the actual state change until we reach the
second lock context, inside the function tipc_node_link_up(). This
makes it possible for potentail callers of __tipc_node_link_down() to
know if they should proceed or not, and the problem is solved.
Unforunately, the situation described above also has a second problem.
Since there by necessity is a tipc_node_link_up() call pending once
the node lock has been released, we must defuse that call by setting
the link back from LINK_ESTABLISHING to LINK_RESET state. This forces
us to make a slight modification to the link FSM, which will now look
as follows.
+------------------------------------+
|RESET_EVT |
| |
| +--------------+
| +-----------------| SYNCHING |-----------------+
| |FAILURE_EVT +--------------+ PEER_RESET_EVT|
| | A | |
| | | | |
| | | | |
| | |SYNCH_ |SYNCH_ |
| | |BEGIN_EVT |END_EVT |
| | | | |
| V | V V
| +-------------+ +--------------+ +------------+
| | RESETTING |<---------| ESTABLISHED |--------->| PEER_RESET |
| +-------------+ FAILURE_ +--------------+ PEER_ +------------+
| | EVT | A RESET_EVT |
| | | | |
| | +----------------+ | |
| RESET_EVT| |RESET_EVT | |
| | | | |
| | | |ESTABLISH_EVT |
| | | +-------------+ | |
| | | | RESET_EVT | | |
| | | | | | |
| V V V | | |
| +-------------+ +--------------+ RESET_EVT|
+--->| RESET |--------->| ESTABLISHING |<----------------+
+-------------+ PEER_ +--------------+
| A RESET_EVT |
| | |
| | |
|FAILOVER_ |FAILOVER_ |FAILOVER_
|BEGIN_EVT |END_EVT |BEGIN_EVT
| | |
V | |
+-------------+ |
| FAILINGOVER |<----------------+
+-------------+
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>
After the previous commits, we are guaranteed that no packets
of type LINK_PROTOCOL or with illegal sequence numbers will be
attempted added to the link deferred queue. This makes it possible to
make some simplifications to the sorting algorithm in the function
tipc_skb_queue_sorted().
We also alter the function so that it will drop packets if one with
the same seqeunce number is already present in the queue. This is
necessary because we have identified weird packet sequences, involving
duplicate packets, where a legitimate in-sequence packet may advance to
the head of the queue without being detected and de-queued.
Finally, we make this function outline, since it will now be called only
in exceptional cases.
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>
The sequence number of an incoming packet is currently only checked
for less than, equality to, or bigger than the next expected number,
meaning that the receive window in practice becomes one half sequence
number cycle, or U16_MAX/2. This does not make sense, and may not even
be safe if there are extreme delays in the network. Any packet sent by
the peer during the ongoing cycle must belong inside his current send
window, or should otherwise be dropped if possible.
Since a link endpoint cannot know its peer's current send window, it
has to base this sanity check on a worst-case assumption, i.e., that
the peer is using a maximum sized window of 8191 packets. Using this
assumption, we now add a check that the sequence number is not bigger
than next_expected + TIPC_MAX_LINK_WIN. We also re-order the checks
done, so that the receive window test is performed before the gap test.
This way, we are guaranteed that no packet with illegal sequence numbers
are ever added to the deferred queue.
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>
Currently, all packets received in tipc_link_rcv() are unconditionally
added to the packet deferred queue, whereafter that queue is walked and
all its buffers evaluated for delivery. This is both non-optimal and
and makes the queue sorting function unnecessary complex.
This commit changes the loop so that an arrived packet is evaluated
first, and added to the deferred queue only when a sequence number gap
is discovered. A non-empty deferred queue is walked until it is empty
or until its head's sequence number doesn't fit.
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>
During packet reception, the function tipc_link_rcv() adds its accepted
packets to a temporary buffer queue, before finally splicing this queue
into the lock protected input queue that will be delivered up to the
socket layer. The purpose is to reduce potential contention on the input
queue lock. However, since the vast majority of packets arrive in
sequence, they will anyway be added one by one to the input queue, and
the use of the temporary queue becomes a sub-optimization.
The only case where this queue makes sense is when unpacking buffers
from a bundle packet; here we want to avoid dozens of small buffers
to be added individually to the lock-protected input queue in a tight
loop.
In this commit, we remove the general usage of the temporary queue,
and keep it only for the packet unbundling case.
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>
In commit e3eea1eb47 ("tipc: clean up handling of message priorities")
we introduced a field in the packet header for keeping track of the
priority of fragments, since this value is not present in the specified
protocol header. Since the value so far only is used at the transmitting
end of the link, we have not yet officially defined it as part of the
protocol.
Unfortunately, the field we use for keeping this value, bits 13-15 in
in word 5, has turned out to be a poor choice; it is already used by the
broadcast protocol for carrying the 'network id' field of the sending
node. Since packet fragments also need to be transported across the
broadcast protocol, the risk of conflict is obvious, and we see this
happen when we use network identities larger than 2^13-1. This has
escaped our testing because we have so far only been using small network
id values.
We now move this field to bits 0-2 in word 9, a field that is guaranteed
to be unused by all involved protocols.
Fixes: e3eea1eb47 ("tipc: clean up handling of message priorities")
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>
In commit 6e498158a8 ("tipc: move link synch and failover to link aggregation level")
we introduced a new mechanism for performing link failover and
synchronization. We have now detected a bug in this mechanism.
During link synchronization we use the arrival of any packet on
the tunnel link to trig a check for whether it has reached the
synchronization point or not. This has turned out to be too
permissive, since it may cause an arriving non-last SYNCH packet to
end the synch state, just to see the next SYNCH packet initiate a
new synch state with a new, higher synch point. This is not fatal,
but should be avoided, because it may significantly extend the
synchronization period, while at the same time we are not allowed
to send NACKs if packets are lost. In the worst case, a low-traffic
user may see its traffic stall until a LINK_PROTOCOL state message
trigs the link to leave synchronization state.
At the same time, LINK_PROTOCOL packets which happen to have a (non-
valid) sequence number lower than the tunnel link's rcv_nxt value will
be consistently dropped, and will never be able to resolve the situation
described above.
We fix this by exempting LINK_PROTOCOL packets from the sequence number
check, as they should be. We also reduce (but don't completely
eliminate) the risk of entering multiple synchronization states by only
allowing the (logically) first SYNCH packet to initiate a synchronization
state. This works independently of actual packet arrival order.
Fixes: commit 6e498158a8 ("tipc: move link synch and failover to link aggregation level")
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>
The msg pointer into header may change after skb linearization.
We must reinitialize it after calling skb_linearize to prevent
operating on a freed or invalid pointer.
Signed-off-by: Erik Hugne <erik.hugne@ericsson.com>
Reported-by: Tamás Végh <tamas.vegh@ericsson.com>
Acked-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
If an attempt to wake up users of broadcast link is made when there is
no enough place in send queue than it may hang up inside the
tipc_sk_rcv() function since the loop breaks only after the wake up
queue becomes empty. This can lead to complete CPU stall with the
following message generated by RCU:
INFO: rcu_sched self-detected stall on CPU { 0} (t=2101 jiffies
g=54225 c=54224 q=11465)
Task dump for CPU 0:
tpch R running task 0 39949 39948 0x0000000a
ffffffff818536c0 ffff88181fa037a0 ffffffff8106a4be 0000000000000000
ffffffff818536c0 ffff88181fa037c0 ffffffff8106d8a8 ffff88181fa03800
0000000000000001 ffff88181fa037f0 ffffffff81094a50 ffff88181fa15680
Call Trace:
<IRQ> [<ffffffff8106a4be>] sched_show_task+0xae/0x120
[<ffffffff8106d8a8>] dump_cpu_task+0x38/0x40
[<ffffffff81094a50>] rcu_dump_cpu_stacks+0x90/0xd0
[<ffffffff81097c3b>] rcu_check_callbacks+0x3eb/0x6e0
[<ffffffff8106e53f>] ? account_system_time+0x7f/0x170
[<ffffffff81099e64>] update_process_times+0x34/0x60
[<ffffffff810a84d1>] tick_sched_handle.isra.18+0x31/0x40
[<ffffffff810a851c>] tick_sched_timer+0x3c/0x70
[<ffffffff8109a43d>] __run_hrtimer.isra.34+0x3d/0xc0
[<ffffffff8109aa95>] hrtimer_interrupt+0xc5/0x1e0
[<ffffffff81030d52>] ? native_smp_send_reschedule+0x42/0x60
[<ffffffff81032f04>] local_apic_timer_interrupt+0x34/0x60
[<ffffffff810335bc>] smp_apic_timer_interrupt+0x3c/0x60
[<ffffffff8165a3fb>] apic_timer_interrupt+0x6b/0x70
[<ffffffff81659129>] ? _raw_spin_unlock_irqrestore+0x9/0x10
[<ffffffff8107eb9f>] __wake_up_sync_key+0x4f/0x60
[<ffffffffa313ddd1>] tipc_write_space+0x31/0x40 [tipc]
[<ffffffffa313dadf>] filter_rcv+0x31f/0x520 [tipc]
[<ffffffffa313d699>] ? tipc_sk_lookup+0xc9/0x110 [tipc]
[<ffffffff81659259>] ? _raw_spin_lock_bh+0x19/0x30
[<ffffffffa314122c>] tipc_sk_rcv+0x2dc/0x3e0 [tipc]
[<ffffffffa312e7ff>] tipc_bclink_wakeup_users+0x2f/0x40 [tipc]
[<ffffffffa313ce26>] tipc_node_unlock+0x186/0x190 [tipc]
[<ffffffff81597c1c>] ? kfree_skb+0x2c/0x40
[<ffffffffa313475c>] tipc_rcv+0x2ac/0x8c0 [tipc]
[<ffffffffa312ff58>] tipc_l2_rcv_msg+0x38/0x50 [tipc]
[<ffffffff815a76d3>] __netif_receive_skb_core+0x5a3/0x950
[<ffffffff815a98d3>] __netif_receive_skb+0x13/0x60
[<ffffffff815a993e>] netif_receive_skb_internal+0x1e/0x90
[<ffffffff815aa138>] napi_gro_receive+0x78/0xa0
[<ffffffffa07f93f4>] tg3_poll_work+0xc54/0xf40 [tg3]
[<ffffffff81597c8c>] ? consume_skb+0x2c/0x40
[<ffffffffa07f9721>] tg3_poll_msix+0x41/0x160 [tg3]
[<ffffffff815ab0f2>] net_rx_action+0xe2/0x290
[<ffffffff8104b92a>] __do_softirq+0xda/0x1f0
[<ffffffff8104bc26>] irq_exit+0x76/0xa0
[<ffffffff81004355>] do_IRQ+0x55/0xf0
[<ffffffff8165a12b>] common_interrupt+0x6b/0x6b
<EOI>
The issue occurs only when tipc_sk_rcv() is used to wake up postponed
senders:
tipc_bclink_wakeup_users()
// wakeupq - is a queue which consists of special
// messages with SOCK_WAKEUP type.
tipc_sk_rcv(wakeupq)
...
while (skb_queue_len(inputq)) {
filter_rcv(skb)
// Here the type of message is checked
// and if it is SOCK_WAKEUP then
// it tries to wake up a sender.
tipc_write_space(sk)
wake_up_interruptible_sync_poll()
}
After the sender thread is woke up it can gather control and perform
an attempt to send a message. But if there is no enough place in send
queue it will call link_schedule_user() function which puts a message
of type SOCK_WAKEUP to the wakeup queue and put the sender to sleep.
Thus the size of the queue actually is not changed and the while()
loop never exits.
The approach I proposed is to wake up only senders for which there is
enough place in send queue so the described issue can't occur.
Moreover the same approach is already used to wake up senders on
unicast links.
I have got into the issue on our product code but to reproduce the
issue I changed a benchmark test application (from
tipcutils/demos/benchmark) to perform the following scenario:
1. Run 64 instances of test application (nodes). It can be done
on the one physical machine.
2. Each application connects to all other using TIPC sockets in
RDM mode.
3. When setup is done all nodes start simultaneously send
broadcast messages.
4. Everything hangs up.
The issue is reproducible only when a congestion on broadcast link
occurs. For example, when there are only 8 nodes it works fine since
congestion doesn't occur. Send queue limit is 40 in my case (I use a
critical importance level) and when 64 nodes send a message at the
same moment a congestion occurs every time.
Signed-off-by: Dmitry S Kolmakov <kolmakov.dmitriy@huawei.com>
Reviewed-by: Jon Maloy <jon.maloy@ericsson.com>
Acked-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Recent changes to the link synchronization means that we can now just
drop packets arriving on the synchronizing link before the synch point
is reached. This has lead to significant simplifications to the
implementation, but also turns out to have a flip side that we need
to consider.
Under unlucky circumstances, the two endpoints may end up
repeatedly dropping each other's packets, while immediately
asking for retransmission of the same packets, just to drop
them once more. This pattern will eventually be broken when
the synch point is reached on the other link, but before that,
the endpoints may have arrived at the retransmission limit
(stale counter) that indicates that the link should be broken.
We see this happen at rare occasions.
The fix for this is to not ask for retransmissions when a link is in
state LINK_SYNCHING. The fact that the link has reached this state
means that it has already received the first SYNCH packet, and that it
knows the synch point. Hence, it doesn't need any more packets until the
other link has reached the synch point, whereafter it can go ahead and
ask for the missing packets.
However, because of the reduced traffic on the synching link that
follows this change, it may now take longer to discover that the
synch point has been reached. We compensate for this by letting all
packets, on any of the links, trig a check for synchronization
termination. This is possible because the packets themselves don't
contain any information that is needed for discovering this condition.
Reviewed-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>
When we introduced the new link failover/synch mechanism
in commit 6e498158a8
("tipc: move link synch and failover to link aggregation level"),
we missed the case when the non-tunnel link goes down during the link
synchronization period. In this case the tunnel link will remain in
state LINK_SYNCHING, something leading to unpredictable behavior when
the failover procedure is initiated.
In this commit, we ensure that the node and remaining link goes
back to regular communication state (SELF_UP_PEER_UP/LINK_ESTABLISHED)
when one of the parallel links goes down. We also ensure that we don't
re-enter synch mode if subsequent SYNCH packets arrive on the remaining
link.
Reviewed-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>
When a link goes down, and there is still a working link towards its
destination node, a failover is initiated, and the failed link is not
allowed to re-establish until that procedure is finished. To ensure
this, the concerned link endpoints are set to state LINK_FAILINGOVER,
and the node endpoints to NODE_FAILINGOVER during the failover period.
However, if the link reset is due to a disabled bearer, the corres-
ponding link endpoint is deleted, and only the node endpoint knows
about the ongoing failover. Now, if the disabled bearer is re-enabled
during the failover period, the discovery mechanism may create a new
link endpoint that is ready to be established, despite that this is not
permitted. This situation may cause both the ongoing failover and any
subsequent link synchronization to fail.
In this commit, we ensure that a newly created link goes directly to
state LINK_FAILINGOVER if the corresponding node state is
NODE_FAILINGOVER. This eliminates the problem described above.
Furthermore, we tighten the criteria for which packets are allowed
to end a failover state in the function tipc_node_check_state().
By checking that the receiving link is up and running, instead of just
checking that it is not in failover mode, we eliminate the risk that
protocol packets from the re-created link may cause the failover to
be prematurely terminated.
Reviewed-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>
A zero length payload means that no TLV (Type Length Value) data has
been passed. Prior to this patch a non-existing TLV could be sanity
checked with TLV_OK() resulting in random behavior where a user
sending an empty message occasionally got a incorrect "operation not
supported" message back.
Signed-off-by: Richard Alpe <richard.alpe@ericsson.com>
Reviewed-by: Erik Hugne <erik.hugne@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch adds net argument to ipv6_stub_impl.ipv6_dst_lookup
for use cases where sk is not available (like mpls).
sk appears to be needed to get the namespace 'net' and is optional
otherwise. This patch series changes ipv6_stub_impl.ipv6_dst_lookup
to take net argument. sk remains optional.
All callers of ipv6_stub_impl.ipv6_dst_lookup have been modified
to pass net. I have modified them to use already available
'net' in the scope of the call. I can change them to
sock_net(sk) to avoid any unintended change in behaviour if sock
namespace is different. They dont seem to be from code inspection.
Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
We simplify the link creation function tipc_link_create() and the way
the link struct it is connected to the node struct. In particular, we
remove the duplicate initialization of some fields which are anyway set
in tipc_link_reset().
Tested-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>
Currently, when we extract small messages from a message bundle, or
when many messages have accumulated in the link arrival queue, those
messages are added one by one to the lock protected link input queue.
This may increase contention with the reader of that queue, in
the function tipc_sk_rcv().
This commit introduces a temporary, unprotected input queue in
tipc_link_rcv() for such cases. Only when the arrival queue has been
emptied, and the function is ready to return, does it splice the whole
temporary queue into the real input queue.
Tested-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>
After the most recent changes, all access calls to a link which
may entail addition of messages to the link's input queue are
postpended by an explicit call to tipc_sk_rcv(), using a reference
to the correct queue.
This means that the potentially hazardous implicit delivery, using
tipc_node_unlock() in combination with a binary flag and a cached
queue pointer, now has become redundant.
This commit removes this implicit delivery mechanism both for regular
data messages and for binding table update messages.
Tested-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>
In order to facilitate future improvements to the locking structure, we
want to make resetting and establishing of links non-atomic. I.e., the
functions tipc_node_link_up() and tipc_node_link_down() should be called
from outside the node lock context, and grab/release the node lock
themselves. This requires that we can freeze the link state from the
moment it is set to RESETTING or PEER_RESET in one lock context until
it is set to RESET or ESTABLISHING in a later context. The recently
introduced link FSM makes this possible, so we are now ready to introduce
the above change.
This commit implements this.
Tested-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>
The node lock is currently grabbed and and released in the function
tipc_disc_rcv() in the file discover.c. As a preparation for the next
commits, we need to move this node lock handling, along with the code
area it is covering, to node.c.
This commit introduces this change.
Tested-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>
Until now, we have been handling link failover and synchronization
by using an additional link state variable, "exec_mode". This variable
is not independent of the link FSM state, something causing a risk of
inconsistencies, apart from the fact that it clutters the code.
The conditions are now in place to define a new link FSM that covers
all existing use cases, including failover and synchronization, and
eliminate the "exec_mode" field altogether. The FSM must also support
non-atomic resetting of links, which will be introduced later.
The new link FSM is shown below, with 7 states and 8 events.
Only events leading to state change are shown as edges.
+------------------------------------+
|RESET_EVT |
| |
| +--------------+
| +-----------------| SYNCHING |-----------------+
| |FAILURE_EVT +--------------+ PEER_RESET_EVT|
| | A | |
| | | | |
| | | | |
| | |SYNCH_ |SYNCH_ |
| | |BEGIN_EVT |END_EVT |
| | | | |
| V | V V
| +-------------+ +--------------+ +------------+
| | RESETTING |<---------| ESTABLISHED |--------->| PEER_RESET |
| +-------------+ FAILURE_ +--------------+ PEER_ +------------+
| | EVT | A RESET_EVT |
| | | | |
| | | | |
| | +--------------+ | |
| RESET_EVT| |RESET_EVT |ESTABLISH_EVT |
| | | | |
| | | | |
| V V | |
| +-------------+ +--------------+ RESET_EVT|
+--->| RESET |--------->| ESTABLISHING |<----------------+
+-------------+ PEER_ +--------------+
| A RESET_EVT |
| | |
| | |
|FAILOVER_ |FAILOVER_ |FAILOVER_
|BEGIN_EVT |END_EVT |BEGIN_EVT
| | |
V | |
+-------------+ |
| FAILINGOVER |<----------------+
+-------------+
These changes are fully backwards compatible.
Tested-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>
The implementation of the link FSM currently takes decisions about and
sends out link protocol messages. This is unnecessary, since such
actions are not the result of any link state change, and are even
decided based on non-FSM state information ("silent_intv_cnt").
We now move the sending of unicast link protocol messages to the
function tipc_link_timeout(), and the initial broadcast synchronization
message to tipc_node_link_up(). The latter is done because a link
instance should not need to know whether it is the first or second
link to a destination. Such information is now restricted to and
handled by the link aggregation layer in node.c
Tested-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>
