Re: [PATCH net v1] tipc: fix random link resets while adding a second bearer

[David Miller <davem@davemloft.net>]

From: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com>
Date: Thu, 1 Sep 2016 16:22:16 +0200

> In a dual bearer configuration, if the second tipc link becomes
> active while the first link still has pending nametable "bulk"
> updates, it randomly leads to reset of the second link.
> 
> When a link is established, the function named_distribute(),
> fills the skb based on node mtu (allows room for TUNNEL_PROTOCOL)
> with NAME_DISTRIBUTOR message for each PUBLICATION.
> However, the function named_distribute() allocates the buffer by
> increasing the node mtu by INT_H_SIZE (to insert NAME_DISTRIBUTOR).
> This consumes the space allocated for TUNNEL_PROTOCOL.
> 
> When establishing the second link, the link shall tunnel all the
> messages in the first link queue including the "bulk" update.
> As size of the NAME_DISTRIBUTOR messages while tunnelling, exceeds
> the link mtu the transmission fails (-EMSGSIZE).
> 
> Thus, the synch point based on the message count of the tunnel
> packets is never reached leading to link timeout.
> 
> In this commit, we adjust the size of name distributor message so that
> they can be tunnelled.
> 
> Reviewed-by: Jon Maloy <jon.maloy@ericsson.com>
> Signed-off-by: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com>

Applied.

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