Commit 9a650838 authored Nov 19, 2015 by Jon Paul Maloy Committed by David S. Miller Nov 20, 2015

tipc: correct settings of broadcast link state



Since commit 52666986 ("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>

parent 52dfc830

net/tipc/link.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -191,6 +191,7 @@ void tipc_link_add_bc_peer(struct tipc_link *snd_l,

		snd_l->ackers++;
		rcv_l->acked = snd_l->snd_nxt - 1;
		snd_l->state = LINK_ESTABLISHED;
		tipc_link_build_bc_init_msg(uc_l, xmitq);
		}

		@@ -206,6 +207,7 @@ void tipc_link_remove_bc_peer(struct tipc_link *snd_l,
		rcv_l->state = LINK_RESET;
		if (!snd_l->ackers) {
		tipc_link_reset(snd_l);
		snd_l->state = LINK_RESET;
		__skb_queue_purge(xmitq);
		}
		}

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