tipc: Ignore broadcast acknowledgements that are out-of-range

Adds checks to TIPC's broadcast link so that it ignores any
acknowledgement message containing a sequence number that does not
correspond to an unacknowledged message currently in the broadcast
link's transmit queue.

This change prevents the broadcast link from becoming stalled if a
newly booted node receives stale broadcast link acknowledgement
information from another node that has not yet fully synchronized
its end of the broadcast link to reflect the current state of the
new node's end.

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/net/tipc/bcast.c b/net/tipc/bcast.c
index 4609819ea807c2e61c5a06b1bfc8cfbb81da3679..15eb74458748250d946dff3d74a6b6f173d58a00 100644 (file)
--- a/net/tipc/bcast.c
+++ b/net/tipc/bcast.c
@@ -237,14 +237,36 @@ void tipc_bclink_acknowledge(struct tipc_node *n_ptr, u32 acked)
        struct sk_buff *next;
        unsigned int released = 0;
 
-       if (less_eq(acked, n_ptr->bclink.acked))
-               return;
-
        spin_lock_bh(&bc_lock);
 
-       /* Skip over packets that node has previously acknowledged */
-
+       /* Bail out if tx queue is empty (no clean up is required) */
        crs = bcl->first_out;
+       if (!crs)
+               goto exit;
+
+       /* Determine which messages need to be acknowledged */
+       if (acked == INVALID_LINK_SEQ) {
+               /*
+                * Contact with specified node has been lost, so need to
+                * acknowledge sent messages only (if other nodes still exist)
+                * or both sent and unsent messages (otherwise)
+                */
+               if (bclink->bcast_nodes.count)
+                       acked = bcl->fsm_msg_cnt;
+               else
+                       acked = bcl->next_out_no;
+       } else {
+               /*
+                * Bail out if specified sequence number does not correspond
+                * to a message that has been sent and not yet acknowledged
+                */
+               if (less(acked, buf_seqno(crs)) ||
+                   less(bcl->fsm_msg_cnt, acked) ||
+                   less_eq(acked, n_ptr->bclink.acked))
+                       goto exit;
+       }
+
+       /* Skip over packets that node has previously acknowledged */
        while (crs && less_eq(buf_seqno(crs), n_ptr->bclink.acked))
                crs = crs->next;
 
@@ -255,8 +277,6 @@ void tipc_bclink_acknowledge(struct tipc_node *n_ptr, u32 acked)
 
                if (crs != bcl->next_out)
                        bcbuf_decr_acks(crs);
-               else if (bclink->bcast_nodes.count)
-                       break;
                else {
                        bcbuf_set_acks(crs, 0);
                        bcl->next_out = next;
@@ -281,6 +301,7 @@ void tipc_bclink_acknowledge(struct tipc_node *n_ptr, u32 acked)
        }
        if (unlikely(released && !list_empty(&bcl->waiting_ports)))
                tipc_link_wakeup_ports(bcl, 0);
+exit:
        spin_unlock_bh(&bc_lock);
 }
 

diff --git a/net/tipc/link.c b/net/tipc/link.c
index 332915e43043e362389ecc05c923d1492cd0787b..4eff342326e2e909b783ec00c7509b81fea4a5e5 100644 (file)
--- a/net/tipc/link.c
+++ b/net/tipc/link.c
@@ -1733,10 +1733,8 @@ void tipc_recv_msg(struct sk_buff *head, struct tipc_bearer *b_ptr)
 
                /* Release acked messages */
 
-               if (less(n_ptr->bclink.acked, msg_bcast_ack(msg))) {
-                       if (tipc_node_is_up(n_ptr) && n_ptr->bclink.supported)
-                               tipc_bclink_acknowledge(n_ptr, msg_bcast_ack(msg));
-               }
+               if (tipc_node_is_up(n_ptr) && n_ptr->bclink.supported)
+                       tipc_bclink_acknowledge(n_ptr, msg_bcast_ack(msg));
 
                crs = l_ptr->first_out;
                while ((crs != l_ptr->next_out) &&

diff --git a/net/tipc/link.h b/net/tipc/link.h
index e56cb532913e0fa72f278c90aea1ecbc7846cce8..78792399d667866c5b408db226dbab5a384df876 100644 (file)
--- a/net/tipc/link.h
+++ b/net/tipc/link.h
@@ -44,6 +44,12 @@
 #define PUSH_FAILED   1
 #define PUSH_FINISHED 2
 
+/*
+ * Out-of-range value for link sequence numbers
+ */
+
+#define INVALID_LINK_SEQ 0x10000
+
 /*
  * Link states
  */

diff --git a/net/tipc/node.c b/net/tipc/node.c
index 1861ae915f17b5e88391aee6284869066aea54ef..e530de279be958771fc3e1f471e84a55f50f76af 100644 (file)
--- a/net/tipc/node.c
+++ b/net/tipc/node.c
@@ -351,8 +351,7 @@ static void node_lost_contact(struct tipc_node *n_ptr)
                }
 
                tipc_bclink_remove_node(n_ptr->addr);
-               tipc_bclink_acknowledge(n_ptr,
-                                       mod(n_ptr->bclink.acked + 10000));
+               tipc_bclink_acknowledge(n_ptr, INVALID_LINK_SEQ);
                if (n_ptr->addr < tipc_own_addr)
                        tipc_own_tag--;