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

tipc: clean up skb list lock handling on send path

2019-08-18T21:01:07Z

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 Reported-by: Chris Packham Acked-by: Ying Xue Signed-off-by: Jon Maloy Reviewed-by: Xin Long Signed-off-by: David S. Miller

tipc: add loopback device tracking

2019-08-09T05:11:39Z

Since node internal messages are passed directly to the socket, it is not possible to observe those messages via tcpdump or wireshark. We now remedy this by making it possible to clone such messages and send the clones to the loopback interface. The clones are dropped at reception and have no functional role except making the traffic visible. The feature is enabled if network taps are active for the loopback device. pcap filtering restrictions require the messages to be presented to the receiving side of the loopback device. v3 - Function dev_nit_active used to check for network taps. - Procedure netif_rx_ni used to send cloned messages to loopback device. Signed-off-by: John Rutherford Acked-by: Jon Maloy Acked-by: Ying Xue Signed-off-by: David S. Miller

tipc: optimize link synching mechanism

2019-07-25T22:55:47Z

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

tipc: initialize 'validated' field of received packets

2019-07-17T22:24:38Z

The tipc_msg_validate() function leaves a boolean flag 'validated' in the validated buffer's control block, to avoid performing this action more than once. However, at reception of new packets, the position of this field may already have been set by lower layer protocols, so that the packet is erroneously perceived as already validated by TIPC. We fix this by initializing the said field to 'false' before performing the initial validation. Signed-off-by: Jon Maloy Signed-off-by: David S. Miller

tipc: rename function msg_get_wrapped() to msg_inner_hdr()

2019-06-25T20:42:54Z

We rename the inline function msg_get_wrapped() to the more comprehensible msg_inner_hdr(). Signed-off-by: Jon Maloy Signed-off-by: David S. Miller

tipc: fix issues with early FAILOVER_MSG from peer

2019-06-18T17:03:37Z

It appears that a FAILOVER_MSG can come from peer even when the failure link is resetting (i.e. just after the 'node_write_unlock()'...). This means the failover procedure on the node has not been started yet. The situation is as follows: node1 node2 linkb linka linka linkb | | | | | | x failure | | | RESETTING | | | | | | x failure RESET | | RESETTING FAILINGOVER | | | (FAILOVER_MSG) | | |<-------------------------------------------------| | *FAILINGOVER | | | | | (dummy FAILOVER_MSG) | | |------------------------------------------------->| | RESET | | FAILOVER_END | FAILINGOVER RESET | . . . . . . . . . . . . Once this happens, the link failover procedure will be triggered wrongly on the receiving node since the node isn't in FAILINGOVER state but then another link failover will be carried out. The consequences are: 1) A peer might get stuck in FAILINGOVER state because the 'sync_point' was set, reset and set incorrectly, the criteria to end the failover would not be met, it could keep waiting for a message that has already received. 2) The early FAILOVER_MSG(s) could be queued in the link failover deferdq but would be purged or not pulled out because the 'drop_point' was not set correctly. 3) The early FAILOVER_MSG(s) could be dropped too. 4) The dummy FAILOVER_MSG could make the peer leaving FAILINGOVER state shortly, but later on it would be restarted. The same situation can also happen when the link is in PEER_RESET state and a FAILOVER_MSG arrives. The commit resolves the issues by forcing the link down immediately, so the failover procedure will be started normally (which is the same as when receiving a FAILOVER_MSG and the link is in up state). Also, the function "tipc_node_link_failover()" is toughen to avoid such a situation from happening. Acked-by: Jon Maloy Signed-off-by: Tuong Lien Signed-off-by: David S. Miller

tipc: fix missing Name entries due to half-failover

2019-05-04T04:59:51Z

TIPC link can temporarily fall into "half-establish" that only one of the link endpoints is ESTABLISHED and starts to send traffic, PROTOCOL messages, whereas the other link endpoint is not up (e.g. immediately when the endpoint receives ACTIVATE_MSG, the network interface goes down...). This is a normal situation and will be settled because the link endpoint will be eventually brought down after the link tolerance time. However, the situation will become worse when the second link is established before the first link endpoint goes down, For example: 1. Both links <1A-2A>, <1B-2B> down 2. Link endpoint 2A up, but 1A still down (e.g. due to network disturbance, wrong session, etc.) 3. Link <1B-2B> up 4. Link endpoint 2A down (e.g. due to link tolerance timeout) 5. Node B starts failover onto link <1B-2B> ==> Node A does never start link failover. When the "half-failover" situation happens, two consequences have been observed: a) Peer link/node gets stuck in FAILINGOVER state; b) Traffic or user messages that peer node is trying to failover onto the second link can be partially or completely dropped by this node. The consequence a) was actually solved by commit c140eb166d68 ("tipc: fix failover problem"), but that commit didn't cover the b). It's due to the fact that the tunnel link endpoint has never been prepared for a failover, so the 'l->drop_point' (and the other data...) is not set correctly. When a TUNNEL_MSG from peer node arrives on the link, depending on the inner message's seqno and the current 'l->drop_point' value, the message can be dropped (- treated as a duplicate message) or processed. At this early stage, the traffic messages from peer are likely to be NAME_DISTRIBUTORs, this means some name table entries will be missed on the node forever! The commit resolves the issue by starting the FAILOVER process on this node as well. Another benefit from this solution is that we ensure the link will not be re-established until the failover ends. Acked-by: Jon Maloy Signed-off-by: Tuong Lien Signed-off-by: David S. Miller

netlink: make validation more configurable for future strictness

2019-04-27T21:07:21Z

We currently have two levels of strict validation: 1) liberal (default) - undefined (type >= max) & NLA_UNSPEC attributes accepted - attribute length >= expected accepted - garbage at end of message accepted 2) strict (opt-in) - NLA_UNSPEC attributes accepted - attribute length >= expected accepted Split out parsing strictness into four different options: * TRAILING - check that there's no trailing data after parsing attributes (in message or nested) * MAXTYPE - reject attrs > max known type * UNSPEC - reject attributes with NLA_UNSPEC policy entries * STRICT_ATTRS - strictly validate attribute size The default for future things should be *everything*. The current *_strict() is a combination of TRAILING and MAXTYPE, and is renamed to _deprecated_strict(). The current regular parsing has none of this, and is renamed to *_parse_deprecated(). Additionally it allows us to selectively set one of the new flags even on old policies. Notably, the UNSPEC flag could be useful in this case, since it can be arranged (by filling in the policy) to not be an incompatible userspace ABI change, but would then going forward prevent forgetting attribute entries. Similar can apply to the POLICY flag. We end up with the following renames: * nla_parse -> nla_parse_deprecated * nla_parse_strict -> nla_parse_deprecated_strict * nlmsg_parse -> nlmsg_parse_deprecated * nlmsg_parse_strict -> nlmsg_parse_deprecated_strict * nla_parse_nested -> nla_parse_nested_deprecated * nla_validate_nested -> nla_validate_nested_deprecated Using spatch, of course: @@ expression TB, MAX, HEAD, LEN, POL, EXT; @@ -nla_parse(TB, MAX, HEAD, LEN, POL, EXT) +nla_parse_deprecated(TB, MAX, HEAD, LEN, POL, EXT) @@ expression NLH, HDRLEN, TB, MAX, POL, EXT; @@ -nlmsg_parse(NLH, HDRLEN, TB, MAX, POL, EXT) +nlmsg_parse_deprecated(NLH, HDRLEN, TB, MAX, POL, EXT) @@ expression NLH, HDRLEN, TB, MAX, POL, EXT; @@ -nlmsg_parse_strict(NLH, HDRLEN, TB, MAX, POL, EXT) +nlmsg_parse_deprecated_strict(NLH, HDRLEN, TB, MAX, POL, EXT) @@ expression TB, MAX, NLA, POL, EXT; @@ -nla_parse_nested(TB, MAX, NLA, POL, EXT) +nla_parse_nested_deprecated(TB, MAX, NLA, POL, EXT) @@ expression START, MAX, POL, EXT; @@ -nla_validate_nested(START, MAX, POL, EXT) +nla_validate_nested_deprecated(START, MAX, POL, EXT) @@ expression NLH, HDRLEN, MAX, POL, EXT; @@ -nlmsg_validate(NLH, HDRLEN, MAX, POL, EXT) +nlmsg_validate_deprecated(NLH, HDRLEN, MAX, POL, EXT) For this patch, don't actually add the strict, non-renamed versions yet so that it breaks compile if I get it wrong. Also, while at it, make nla_validate and nla_parse go down to a common __nla_validate_parse() function to avoid code duplication. Ultimately, this allows us to have very strict validation for every new caller of nla_parse()/nlmsg_parse() etc as re-introduced in the next patch, while existing things will continue to work as is. In effect then, this adds fully strict validation for any new command. Signed-off-by: Johannes Berg Signed-off-by: David S. Miller

netlink: make nla_nest_start() add NLA_F_NESTED flag

2019-04-27T21:03:44Z

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 Acked-by: Jiri Pirko Acked-by: David Ahern Signed-off-by: David S. Miller

tipc: use standard write_lock & unlock functions when creating node

2019-04-11T20:42:35Z

In the function tipc_node_create() we protect the peer capability field by using the node rw_lock. However, we access the lock directly instead of using the dedicated functions for this, as we do everywhere else in node.c. This cosmetic spot is fixed here. Fixes: 40999f11ce67 ("tipc: make link capability update thread safe") Signed-off-by: Jon Maloy Signed-off-by: David S. Miller