tipc: add sequence number check for link STATE messages

Some switch infrastructures produce huge amounts of packet duplicates.
This becomes a problem if those messages are STATE/NACK protocol
messages, causing unnecessary retransmissions of already accepted
packets.

We now introduce a unique sequence number per STATE protocol message
so that duplicates can be identified and ignored. This will also be
useful when tracing such cases, and to avert replay attacks when TIPC
is encrypted.

For compatibility reasons we have to introduce a new capability flag
TIPC_LINK_PROTO_SEQNO to handle this new feature.

Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 0 deletions

diff --git a/net/tipc/link.h b/net/tipc/link.h
index ec59348a81e8..d56f9c9e5000 100644
--- a/net/tipc/link.h
+++ b/net/tipc/link.h
@@ -110,6 +110,7 @@ char *tipc_link_name(struct tipc_link *l);
 char tipc_link_plane(struct tipc_link *l);
 int tipc_link_prio(struct tipc_link *l);
 int tipc_link_window(struct tipc_link *l);
+void tipc_link_update_caps(struct tipc_link *l, u16 capabilities);
 unsigned long tipc_link_tolerance(struct tipc_link *l);
 void tipc_link_set_tolerance(struct tipc_link *l, u32 tol,
 			     struct sk_buff_head *xmitq);