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authorTuong Lien <tuong.t.lien@dektech.com.au>2019-05-02 17:23:23 +0700
committerDavid S. Miller <davem@davemloft.net>2019-05-04 00:59:51 -0400
commitc0b14a0854fab0a0164aabfe49a76aae9216fe97 (patch)
tree67ed783089967ded1d9578e615076e4d54255ba4 /net/tipc/link.h
parentf24098f80748ea95d53603a7bb7954a41bb3ca1b (diff)
tipc: fix missing Name entries due to half-failover
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 <jon.maloy@ericsson.com> Signed-off-by: Tuong Lien <tuong.t.lien@dektech.com.au> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/tipc/link.h')
-rw-r--r--net/tipc/link.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/net/tipc/link.h b/net/tipc/link.h
index 8439e0ee53a8..adcad65e761c 100644
--- a/net/tipc/link.h
+++ b/net/tipc/link.h
@@ -90,6 +90,8 @@ void tipc_link_tnl_prepare(struct tipc_link *l, struct tipc_link *tnl,
int mtyp, struct sk_buff_head *xmitq);
void tipc_link_create_dummy_tnl_msg(struct tipc_link *tnl,
struct sk_buff_head *xmitq);
+void tipc_link_failover_prepare(struct tipc_link *l, struct tipc_link *tnl,
+ struct sk_buff_head *xmitq);
void tipc_link_build_reset_msg(struct tipc_link *l, struct sk_buff_head *xmitq);
int tipc_link_fsm_evt(struct tipc_link *l, int evt);
bool tipc_link_is_up(struct tipc_link *l);