tipc: introduce capability bit for broadcast synchronization

Until now, we have tried to support both the newer, dedicated broadcast
synchronization mechanism along with the older, less safe, RESET_MSG/
ACTIVATE_MSG based one. The latter method has turned out to be a hazard
in a highly dynamic cluster, so we find it safer to disable it completely
when we find that the former mechanism is supported by the peer node.

For this purpose, we now introduce a new capabability bit,
TIPC_BCAST_SYNCH, to inform any peer nodes that dedicated broadcast
syncronization is supported by the present node. The new bit is conveyed
between peers in the 'capabilities' field of neighbor discovery messages.

Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Reviewed-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 2 deletions

diff --git a/net/tipc/link.h b/net/tipc/link.h
index 9c4acc26b3b1..d23329db4b25 100644
--- a/net/tipc/link.h
+++ b/net/tipc/link.h
@@ -119,6 +119,7 @@ struct tipc_stats {
  * @keepalive_intv: link keepalive timer interval
  * @abort_limit: # of unacknowledged continuity probes needed to reset link
  * @state: current state of link FSM
+ * @peer_caps: bitmap describing capabilities of peer node
  * @silent_intv_cnt: # of timer intervals without any reception from peer
  * @proto_msg: template for control messages generated by link
  * @pmsg: convenience pointer to "proto_msg" field
@@ -162,6 +163,7 @@ struct tipc_link {
         unsigned long keepalive_intv;
         u32 abort_limit;
         u32 state;
+        u16 peer_caps;
         u32 silent_intv_cnt;
         struct {
                 unchar hdr[INT_H_SIZE];
@@ -215,11 +217,11 @@ struct tipc_link {
 bool tipc_link_create(struct tipc_node *n, char *if_name, int bearer_id,
                       int tolerance, char net_plane, u32 mtu, int priority,
                       int window, u32 session, u32 ownnode, u32 peer,
-                      struct tipc_media_addr *maddr,
+                      u16 peer_caps, struct tipc_media_addr *maddr,
                       struct sk_buff_head *inputq, struct sk_buff_head *namedq,
                       struct tipc_link **link);
 bool tipc_link_bc_create(struct tipc_node *n, int mtu, int window,
-                         struct sk_buff_head *inputq,
+                         u16 peer_caps, struct sk_buff_head *inputq,
                          struct sk_buff_head *namedq,
                          struct tipc_link **link);
 void tipc_link_tnl_prepare(struct tipc_link *l, struct tipc_link *tnl,