1 files changed, 29 insertions, 5 deletions

diff --git a/net/tipc/socket.c b/net/tipc/socket.c
index 3276b7a0d445..b1f1c3c2b1e2 100644
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -831,6 +831,7 @@ static int tipc_send_group_msg(struct net *net, struct tipc_sock *tsk,
                                u32 dnode, u32 dport, int dlen)
 {
         u16 bc_snd_nxt = tipc_group_bc_snd_nxt(tsk->group);
+        struct tipc_mc_method *method = &tsk->mc_method;
         int blks = tsk_blocks(GROUP_H_SIZE + dlen);
         struct tipc_msg *hdr = &tsk->phdr;
         struct sk_buff_head pkts;
@@ -857,9 +858,12 @@ static int tipc_send_group_msg(struct net *net, struct tipc_sock *tsk,
                 tsk->cong_link_cnt++;
         }
 
-        /* Update send window and sequence number */
+        /* Update send window */
         tipc_group_update_member(mb, blks);
 
+        /* A broadcast sent within next EXPIRE period must follow same path */
+        method->rcast = true;
+        method->mandatory = true;
         return dlen;
 }
 
@@ -1008,6 +1012,7 @@ static int tipc_send_group_bcast(struct socket *sock, struct msghdr *m,
         struct tipc_group *grp = tsk->group;
         struct tipc_nlist *dsts = tipc_group_dests(grp);
         struct tipc_mc_method *method = &tsk->mc_method;
+        bool ack = method->mandatory && method->rcast;
         int blks = tsk_blocks(MCAST_H_SIZE + dlen);
         struct tipc_msg *hdr = &tsk->phdr;
         int mtu = tipc_bcast_get_mtu(net);
@@ -1036,6 +1041,9 @@ static int tipc_send_group_bcast(struct socket *sock, struct msghdr *m,
         msg_set_destnode(hdr, 0);
         msg_set_grp_bc_seqno(hdr, tipc_group_bc_snd_nxt(grp));
 
+        /* Avoid getting stuck with repeated forced replicasts */
+        msg_set_grp_bc_ack_req(hdr, ack);
+
         /* Build message as chain of buffers */
         skb_queue_head_init(&pkts);
         rc = tipc_msg_build(hdr, m, 0, dlen, mtu, &pkts);
@@ -1043,13 +1051,17 @@ static int tipc_send_group_bcast(struct socket *sock, struct msghdr *m,
                 return rc;
 
         /* Send message */
-        rc = tipc_mcast_xmit(net, &pkts, method, dsts,
-                             &tsk->cong_link_cnt);
+        rc = tipc_mcast_xmit(net, &pkts, method, dsts, &tsk->cong_link_cnt);
         if (unlikely(rc))
                 return rc;
 
         /* Update broadcast sequence number and send windows */
-        tipc_group_update_bc_members(tsk->group, blks);
+        tipc_group_update_bc_members(tsk->group, blks, ack);
+
+        /* Broadcast link is now free to choose method for next broadcast */
+        method->mandatory = false;
+        method->expires = jiffies;
+
         return dlen;
 }
 
@@ -1113,7 +1125,7 @@ void tipc_sk_mcast_rcv(struct net *net, struct sk_buff_head *arrvq,
         u32 portid, oport, onode;
         struct list_head dports;
         struct tipc_msg *msg;
-        int hsz;
+        int user, mtyp, hsz;
 
         __skb_queue_head_init(&tmpq);
         INIT_LIST_HEAD(&dports);
@@ -1121,6 +1133,18 @@ void tipc_sk_mcast_rcv(struct net *net, struct sk_buff_head *arrvq,
         skb = tipc_skb_peek(arrvq, &inputq->lock);
         for (; skb; skb = tipc_skb_peek(arrvq, &inputq->lock)) {
                 msg = buf_msg(skb);
+                user = msg_user(msg);
+                mtyp = msg_type(msg);
+                if (mtyp == TIPC_GRP_UCAST_MSG || user == GROUP_PROTOCOL) {
+                        spin_lock_bh(&inputq->lock);
+                        if (skb_peek(arrvq) == skb) {
+                                __skb_dequeue(arrvq);
+                                __skb_queue_tail(inputq, skb);
+                        }
+                        refcount_dec(&skb->users);
+                        spin_unlock_bh(&inputq->lock);
+                        continue;
+                }
                 hsz = skb_headroom(skb) + msg_hdr_sz(msg);
                 oport = msg_origport(msg);
                 onode = msg_orignode(msg);