From c140eb166d681f66bd7e99fb121357db1a503e7f Mon Sep 17 00:00:00 2001 From: LUU Duc Canh Date: Wed, 26 Sep 2018 21:00:54 +0200 Subject: tipc: fix failover problem We see the following scenario: 1) Link endpoint B on node 1 discovers that its peer endpoint is gone. Since there is a second working link, failover procedure is started. 2) Link endpoint A on node 1 sends a FAILOVER message to peer endpoint A on node 2. The node item 1->2 goes to state FAILINGOVER. 3) Linke endpoint A/2 receives the failover, and is supposed to take down its parallell link endpoint B/2, while producing a FAILOVER message to send back to A/1. 4) However, B/2 has already been deleted, so no FAILOVER message can created. 5) Node 1->2 remains in state FAILINGOVER forever, refusing to receive any messages that can bring B/1 up again. We are left with a non- redundant link between node 1 and 2. We fix this with letting endpoint A/2 build a dummy FAILOVER message to send to back to A/1, so that the situation can be resolved. Signed-off-by: LUU Duc Canh Signed-off-by: Jon Maloy Signed-off-by: David S. Miller --- net/tipc/link.c | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) (limited to 'net/tipc/link.c') diff --git a/net/tipc/link.c b/net/tipc/link.c index 26cc033ee167..4ed650ce6e61 100644 --- a/net/tipc/link.c +++ b/net/tipc/link.c @@ -410,6 +410,11 @@ char *tipc_link_name(struct tipc_link *l) return l->name; } +u32 tipc_link_state(struct tipc_link *l) +{ + return l->state; +} + /** * tipc_link_create - create a new link * @n: pointer to associated node @@ -1385,6 +1390,36 @@ static void tipc_link_build_proto_msg(struct tipc_link *l, int mtyp, bool probe, __skb_queue_tail(xmitq, skb); } +void tipc_link_create_dummy_tnl_msg(struct tipc_link *l, + struct sk_buff_head *xmitq) +{ + u32 onode = tipc_own_addr(l->net); + struct tipc_msg *hdr, *ihdr; + struct sk_buff_head tnlq; + struct sk_buff *skb; + u32 dnode = l->addr; + + skb_queue_head_init(&tnlq); + skb = tipc_msg_create(TUNNEL_PROTOCOL, FAILOVER_MSG, + INT_H_SIZE, BASIC_H_SIZE, + dnode, onode, 0, 0, 0); + if (!skb) { + pr_warn("%sunable to create tunnel packet\n", link_co_err); + return; + } + + hdr = buf_msg(skb); + msg_set_msgcnt(hdr, 1); + msg_set_bearer_id(hdr, l->peer_bearer_id); + + ihdr = (struct tipc_msg *)msg_data(hdr); + tipc_msg_init(onode, ihdr, TIPC_LOW_IMPORTANCE, TIPC_DIRECT_MSG, + BASIC_H_SIZE, dnode); + msg_set_errcode(ihdr, TIPC_ERR_NO_PORT); + __skb_queue_tail(&tnlq, skb); + tipc_link_xmit(l, &tnlq, xmitq); +} + /* tipc_link_tnl_prepare(): prepare and return a list of tunnel packets * with contents of the link's transmit and backlog queues. */ -- cgit v1.2.3