Reviewed-by: Jon Maloy
On 08/31/2016 07:35 AM, Parthasarathy Bhuvaragan wrote:
> 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.
>
> Signed-off-by: Parthasarathy Bhuvaragan
> <parthasarathy.bhuvara...@ericsson.com>
> ---
> v3: removed the erroneous usage of roundup() and replaced with exact math
> as reported by Billie Alsup.
> ---
> net/tipc/name_distr.c | 8 +++++---
> 1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/net/tipc/name_distr.c b/net/tipc/name_distr.c
> index 6b626a64b517..a04fe9be1c60 100644
> --- a/net/tipc/name_distr.c
> +++ b/net/tipc/name_distr.c
> @@ -62,6 +62,8 @@ static void publ_to_item(struct distr_item *i, struct
> publication *p)
>
> /**
> * named_prepare_buf - allocate & initialize a publication message
> + *
> + * The buffer returned is of size INT_H_SIZE + payload size
> */
> static struct sk_buff *named_prepare_buf(struct net *net, u32 type, u32
> size,
> u32 dest)
> @@ -141,9 +143,9 @@ static void named_distribute(struct net *net, struct
> sk_buff_head *list,
> struct publication *publ;
> struct sk_buff *skb = NULL;
> struct distr_item *item = NULL;
> - uint msg_dsz = (tipc_node_get_mtu(net, dnode, 0) / ITEM_SIZE) *
> - ITEM_SIZE;
> - uint msg_rem = msg_dsz;
> + u32 msg_dsz = ((tipc_node_get_mtu(net, dnode, 0) - INT_H_SIZE) /
> + ITEM_SIZE) * ITEM_SIZE;
> + u32 msg_rem = msg_dsz;
>
> list_for_each_entry(publ, pls, local_list) {
> /* Prepare next buffer: */
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