tipc: move protocol message sending away from link FSM
[cascardo/linux.git] / net / tipc / node.c
index 6a0680b..9e20acf 100644 (file)
 #include "bcast.h"
 #include "discover.h"
 
+/* Node FSM states and events:
+ */
+enum {
+       SELF_DOWN_PEER_DOWN    = 0xdd,
+       SELF_UP_PEER_UP        = 0xaa,
+       SELF_DOWN_PEER_LEAVING = 0xd1,
+       SELF_UP_PEER_COMING    = 0xac,
+       SELF_COMING_PEER_UP    = 0xca,
+       SELF_LEAVING_PEER_DOWN = 0x1d,
+       NODE_FAILINGOVER       = 0xf0,
+       NODE_SYNCHING          = 0xcc
+};
+
+enum {
+       SELF_ESTABL_CONTACT_EVT = 0xece,
+       SELF_LOST_CONTACT_EVT   = 0x1ce,
+       PEER_ESTABL_CONTACT_EVT = 0x9ece,
+       PEER_LOST_CONTACT_EVT   = 0x91ce,
+       NODE_FAILOVER_BEGIN_EVT = 0xfbe,
+       NODE_FAILOVER_END_EVT   = 0xfee,
+       NODE_SYNCH_BEGIN_EVT    = 0xcbe,
+       NODE_SYNCH_END_EVT      = 0xcee
+};
+
+static void tipc_node_link_down(struct tipc_node *n, int bearer_id);
 static void node_lost_contact(struct tipc_node *n_ptr);
 static void node_established_contact(struct tipc_node *n_ptr);
 static void tipc_node_delete(struct tipc_node *node);
@@ -265,7 +290,7 @@ static void tipc_node_timeout(unsigned long data)
                        tipc_node_calculate_timer(n, l);
                        rc = tipc_link_timeout(l, &xmitq);
                        if (rc & TIPC_LINK_DOWN_EVT)
-                               tipc_link_reset(l);
+                               tipc_node_link_down(n, bearer_id);
                }
                tipc_node_unlock(n);
                maddr = &n->links[bearer_id].maddr;
@@ -281,66 +306,78 @@ static void tipc_node_timeout(unsigned long data)
  *
  * Link becomes active (alone or shared) or standby, depending on its priority.
  */
-void tipc_node_link_up(struct tipc_node *n, int bearer_id)
+static void tipc_node_link_up(struct tipc_node *n, int bearer_id,
+                             struct sk_buff_head *xmitq)
 {
        int *slot0 = &n->active_links[0];
        int *slot1 = &n->active_links[1];
-       struct tipc_link_entry *links = n->links;
-       struct tipc_link *l = n->links[bearer_id].link;
-
-       /* Leave room for tunnel header when returning 'mtu' to users: */
-       links[bearer_id].mtu = l->mtu - INT_H_SIZE;
+       struct tipc_link *ol = node_active_link(n, 0);
+       struct tipc_link *nl = n->links[bearer_id].link;
 
+       if (n->working_links > 1) {
+               pr_warn("Attempt to establish 3rd link to %x\n", n->addr);
+               return;
+       }
        n->working_links++;
        n->action_flags |= TIPC_NOTIFY_LINK_UP;
-       n->link_id = l->peer_bearer_id << 16 | l->bearer_id;
+       n->link_id = nl->peer_bearer_id << 16 | bearer_id;
+
+       /* Leave room for tunnel header when returning 'mtu' to users: */
+       n->links[bearer_id].mtu = nl->mtu - INT_H_SIZE;
 
        tipc_bearer_add_dest(n->net, bearer_id, n->addr);
 
        pr_debug("Established link <%s> on network plane %c\n",
-                l->name, l->net_plane);
+                nl->name, nl->net_plane);
 
-       /* No active links ? => take both active slots */
-       if (!tipc_node_is_up(n)) {
+       /* First link? => give it both slots */
+       if (!ol) {
                *slot0 = bearer_id;
                *slot1 = bearer_id;
+               nl->exec_mode = TIPC_LINK_OPEN;
+               tipc_link_build_bcast_sync_msg(nl, xmitq);
                node_established_contact(n);
                return;
        }
 
-       /* Lower prio than current active ? => no slot */
-       if (l->priority < links[*slot0].link->priority) {
-               pr_debug("New link <%s> becomes standby\n", l->name);
-               return;
-       }
-       tipc_link_dup_queue_xmit(links[*slot0].link, l);
-
-       /* Same prio as current active ? => take one slot */
-       if (l->priority == links[*slot0].link->priority) {
+       /* Second link => redistribute slots */
+       if (nl->priority > ol->priority) {
+               pr_debug("Old link <%s> becomes standby\n", ol->name);
                *slot0 = bearer_id;
-               return;
+               *slot1 = bearer_id;
+       } else if (nl->priority == ol->priority) {
+               *slot0 = bearer_id;
+       } else {
+               pr_debug("New link <%s> is standby\n", nl->name);
        }
 
-       /* Higher prio than current active => take both active slots */
-       pr_debug("Old link <%s> now standby\n", links[*slot0].link->name);
-       *slot0 = bearer_id;
-       *slot1 = bearer_id;
+       /* Prepare synchronization with first link */
+       tipc_link_tnl_prepare(ol, nl, SYNCH_MSG, xmitq);
 }
 
 /**
  * tipc_node_link_down - handle loss of link
  */
-void tipc_node_link_down(struct tipc_node *n, int bearer_id)
+static void tipc_node_link_down(struct tipc_node *n, int bearer_id)
 {
        int *slot0 = &n->active_links[0];
        int *slot1 = &n->active_links[1];
+       struct tipc_media_addr *maddr = &n->links[bearer_id].maddr;
        int i, highest = 0;
-       struct tipc_link *l, *_l;
+       struct tipc_link *l, *_l, *tnl;
+       struct sk_buff_head xmitq;
 
        l = n->links[bearer_id].link;
+       if (!l || !tipc_link_is_up(l))
+               return;
+
+       __skb_queue_head_init(&xmitq);
+
        n->working_links--;
        n->action_flags |= TIPC_NOTIFY_LINK_DOWN;
-       n->link_id = l->peer_bearer_id << 16 | l->bearer_id;
+       n->link_id = l->peer_bearer_id << 16 | bearer_id;
+
+       tipc_bearer_remove_dest(n->net, l->bearer_id, n->addr);
 
        pr_debug("Lost link <%s> on network plane %c\n",
                 l->name, l->net_plane);
@@ -352,6 +389,8 @@ void tipc_node_link_down(struct tipc_node *n, int bearer_id)
                _l = n->links[i].link;
                if (!_l || !tipc_link_is_up(_l))
                        continue;
+               if (_l == l)
+                       continue;
                if (_l->priority < highest)
                        continue;
                if (_l->priority > highest) {
@@ -362,10 +401,20 @@ void tipc_node_link_down(struct tipc_node *n, int bearer_id)
                }
                *slot1 = i;
        }
-       if (tipc_node_is_up(n))
-               tipc_link_failover_send_queue(l);
-       else
+
+       if (!tipc_node_is_up(n)) {
+               tipc_link_reset(l);
                node_lost_contact(n);
+               return;
+       }
+
+       /* There is still a working link => initiate failover */
+       tnl = node_active_link(n, 0);
+       tipc_node_fsm_evt(n, NODE_FAILOVER_BEGIN_EVT);
+       n->sync_point = tnl->rcv_nxt + (U16_MAX / 2 - 1);
+       tipc_link_tnl_prepare(l, tnl, FAILOVER_MSG, &xmitq);
+       tipc_link_reset(l);
+       tipc_bearer_xmit(n->net, tnl->bearer_id, &xmitq, maddr);
 }
 
 bool tipc_node_is_up(struct tipc_node *n)
@@ -403,7 +452,7 @@ bool tipc_node_update_dest(struct tipc_node *n,  struct tipc_bearer *b,
        }
        memcpy(&l->media_addr, maddr, sizeof(*maddr));
        memcpy(curr, maddr, sizeof(*maddr));
-       tipc_link_reset(l);
+       tipc_node_link_down(n, b->identity);
        return true;
 }
 
@@ -418,7 +467,7 @@ void tipc_node_delete_links(struct net *net, int bearer_id)
                tipc_node_lock(n);
                l = n->links[bearer_id].link;
                if (l) {
-                       tipc_link_reset(l);
+                       tipc_node_link_down(n, bearer_id);
                        n->links[bearer_id].link = NULL;
                        n->link_cnt--;
                }
@@ -439,8 +488,9 @@ static void tipc_node_reset_links(struct tipc_node *n)
                tipc_addr_string_fill(addr_string, n->addr));
 
        for (i = 0; i < MAX_BEARERS; i++) {
-               if (n->links[i].link)
-                       tipc_link_reset(n->links[i].link);
+               if (!n->links[i].link)
+                       continue;
+               tipc_node_link_down(n, i);
        }
        tipc_node_unlock(n);
 }
@@ -482,8 +532,12 @@ static void tipc_node_fsm_evt(struct tipc_node *n, int evt)
                case SELF_LOST_CONTACT_EVT:
                case PEER_LOST_CONTACT_EVT:
                        break;
+               case NODE_SYNCH_END_EVT:
+               case NODE_SYNCH_BEGIN_EVT:
+               case NODE_FAILOVER_BEGIN_EVT:
+               case NODE_FAILOVER_END_EVT:
                default:
-                       pr_err("Unknown node fsm evt %x/%x\n", state, evt);
+                       goto illegal_evt;
                }
                break;
        case SELF_UP_PEER_UP:
@@ -494,11 +548,19 @@ static void tipc_node_fsm_evt(struct tipc_node *n, int evt)
                case PEER_LOST_CONTACT_EVT:
                        state = SELF_LEAVING_PEER_DOWN;
                        break;
+               case NODE_SYNCH_BEGIN_EVT:
+                       state = NODE_SYNCHING;
+                       break;
+               case NODE_FAILOVER_BEGIN_EVT:
+                       state = NODE_FAILINGOVER;
+                       break;
                case SELF_ESTABL_CONTACT_EVT:
                case PEER_ESTABL_CONTACT_EVT:
+               case NODE_SYNCH_END_EVT:
+               case NODE_FAILOVER_END_EVT:
                        break;
                default:
-                       pr_err("Unknown node fsm evt %x/%x\n", state, evt);
+                       goto illegal_evt;
                }
                break;
        case SELF_DOWN_PEER_LEAVING:
@@ -510,8 +572,12 @@ static void tipc_node_fsm_evt(struct tipc_node *n, int evt)
                case PEER_ESTABL_CONTACT_EVT:
                case SELF_LOST_CONTACT_EVT:
                        break;
+               case NODE_SYNCH_END_EVT:
+               case NODE_SYNCH_BEGIN_EVT:
+               case NODE_FAILOVER_BEGIN_EVT:
+               case NODE_FAILOVER_END_EVT:
                default:
-                       pr_err("Unknown node fsm evt %x/%x\n", state, evt);
+                       goto illegal_evt;
                }
                break;
        case SELF_UP_PEER_COMING:
@@ -525,8 +591,12 @@ static void tipc_node_fsm_evt(struct tipc_node *n, int evt)
                case SELF_ESTABL_CONTACT_EVT:
                case PEER_LOST_CONTACT_EVT:
                        break;
+               case NODE_SYNCH_END_EVT:
+               case NODE_SYNCH_BEGIN_EVT:
+               case NODE_FAILOVER_BEGIN_EVT:
+               case NODE_FAILOVER_END_EVT:
                default:
-                       pr_err("Unknown node fsm evt %x/%x\n", state, evt);
+                       goto illegal_evt;
                }
                break;
        case SELF_COMING_PEER_UP:
@@ -540,8 +610,12 @@ static void tipc_node_fsm_evt(struct tipc_node *n, int evt)
                case SELF_LOST_CONTACT_EVT:
                case PEER_ESTABL_CONTACT_EVT:
                        break;
+               case NODE_SYNCH_END_EVT:
+               case NODE_SYNCH_BEGIN_EVT:
+               case NODE_FAILOVER_BEGIN_EVT:
+               case NODE_FAILOVER_END_EVT:
                default:
-                       pr_err("Unknown node fsm evt %x/%x\n", state, evt);
+                       goto illegal_evt;
                }
                break;
        case SELF_LEAVING_PEER_DOWN:
@@ -553,49 +627,85 @@ static void tipc_node_fsm_evt(struct tipc_node *n, int evt)
                case PEER_ESTABL_CONTACT_EVT:
                case PEER_LOST_CONTACT_EVT:
                        break;
+               case NODE_SYNCH_END_EVT:
+               case NODE_SYNCH_BEGIN_EVT:
+               case NODE_FAILOVER_BEGIN_EVT:
+               case NODE_FAILOVER_END_EVT:
                default:
-                       pr_err("Unknown node fsm evt %x/%x\n", state, evt);
+                       goto illegal_evt;
+               }
+               break;
+       case NODE_FAILINGOVER:
+               switch (evt) {
+               case SELF_LOST_CONTACT_EVT:
+                       state = SELF_DOWN_PEER_LEAVING;
+                       break;
+               case PEER_LOST_CONTACT_EVT:
+                       state = SELF_LEAVING_PEER_DOWN;
+                       break;
+               case NODE_FAILOVER_END_EVT:
+                       state = SELF_UP_PEER_UP;
+                       break;
+               case NODE_FAILOVER_BEGIN_EVT:
+               case SELF_ESTABL_CONTACT_EVT:
+               case PEER_ESTABL_CONTACT_EVT:
+                       break;
+               case NODE_SYNCH_BEGIN_EVT:
+               case NODE_SYNCH_END_EVT:
+               default:
+                       goto illegal_evt;
+               }
+               break;
+       case NODE_SYNCHING:
+               switch (evt) {
+               case SELF_LOST_CONTACT_EVT:
+                       state = SELF_DOWN_PEER_LEAVING;
+                       break;
+               case PEER_LOST_CONTACT_EVT:
+                       state = SELF_LEAVING_PEER_DOWN;
+                       break;
+               case NODE_SYNCH_END_EVT:
+                       state = SELF_UP_PEER_UP;
+                       break;
+               case NODE_FAILOVER_BEGIN_EVT:
+                       state = NODE_FAILINGOVER;
+                       break;
+               case NODE_SYNCH_BEGIN_EVT:
+               case SELF_ESTABL_CONTACT_EVT:
+               case PEER_ESTABL_CONTACT_EVT:
+                       break;
+               case NODE_FAILOVER_END_EVT:
+               default:
+                       goto illegal_evt;
                }
                break;
        default:
                pr_err("Unknown node fsm state %x\n", state);
                break;
        }
-
        n->state = state;
+       return;
+
+illegal_evt:
+       pr_err("Illegal node fsm evt %x in state %x\n", evt, state);
 }
 
-bool tipc_node_filter_skb(struct tipc_node *n, struct tipc_link *l,
-                         struct tipc_msg *hdr)
+bool tipc_node_filter_pkt(struct tipc_node *n, struct tipc_msg *hdr)
 {
        int state = n->state;
 
        if (likely(state == SELF_UP_PEER_UP))
                return true;
 
-       if (state == SELF_DOWN_PEER_DOWN)
-               return true;
-
-       if (state == SELF_UP_PEER_COMING) {
-               /* If not traffic msg, peer may still be ESTABLISHING */
-               if (tipc_link_is_up(l) && msg_is_traffic(hdr))
-                       tipc_node_fsm_evt(n, PEER_ESTABL_CONTACT_EVT);
-               return true;
-       }
-
-       if (state == SELF_COMING_PEER_UP)
-               return true;
-
        if (state == SELF_LEAVING_PEER_DOWN)
                return false;
 
        if (state == SELF_DOWN_PEER_LEAVING) {
-               if (msg_peer_is_up(hdr))
+               if (msg_peer_node_is_up(hdr))
                        return false;
-               tipc_node_fsm_evt(n, PEER_LOST_CONTACT_EVT);
-               return true;
        }
-       return false;
+
+       return true;
 }
 
 static void node_established_contact(struct tipc_node *n_ptr)
@@ -640,10 +750,8 @@ static void node_lost_contact(struct tipc_node *n_ptr)
                if (!l_ptr)
                        continue;
                l_ptr->exec_mode = TIPC_LINK_OPEN;
-               l_ptr->failover_checkpt = 0;
-               l_ptr->failover_pkts = 0;
-               kfree_skb(l_ptr->failover_skb);
-               l_ptr->failover_skb = NULL;
+               kfree_skb(l_ptr->failover_reasm_skb);
+               l_ptr->failover_reasm_skb = NULL;
                tipc_link_reset_fragments(l_ptr);
        }
        /* Prevent re-contact with node until cleanup is done */
@@ -837,7 +945,7 @@ int tipc_node_xmit(struct net *net, struct sk_buff_head *list,
                if (likely(l))
                        rc = tipc_link_xmit(l, list, &xmitq);
                if (unlikely(rc == -ENOBUFS))
-                       tipc_link_reset(l);
+                       tipc_node_link_down(n, bearer_id);
                tipc_node_unlock(n);
                tipc_node_put(n);
        }
@@ -874,38 +982,111 @@ int tipc_node_xmit_skb(struct net *net, struct sk_buff *skb, u32 dnode,
        return 0;
 }
 
-/* tipc_node_tnl_init(): handle a received TUNNEL_PROTOCOL packet,
- * in order to control parallel link failover or synchronization
+/**
+ * tipc_node_check_state - check and if necessary update node state
+ * @skb: TIPC packet
+ * @bearer_id: identity of bearer delivering the packet
+ * Returns true if state is ok, otherwise consumes buffer and returns false
  */
-static void tipc_node_tnl_init(struct tipc_node *n, int bearer_id,
-                              struct sk_buff *skb)
+static bool tipc_node_check_state(struct tipc_node *n, struct sk_buff *skb,
+                                 int bearer_id)
 {
-       struct tipc_link *tnl, *pl;
        struct tipc_msg *hdr = buf_msg(skb);
+       int usr = msg_user(hdr);
+       int mtyp = msg_type(hdr);
        u16 oseqno = msg_seqno(hdr);
-       int pb_id = msg_bearer_id(hdr);
+       u16 iseqno = msg_seqno(msg_get_wrapped(hdr));
+       u16 exp_pkts = msg_msgcnt(hdr);
+       u16 rcv_nxt, syncpt, dlv_nxt;
+       int state = n->state;
+       struct tipc_link *l, *pl = NULL;
+       struct sk_buff_head;
+       int i;
 
-       if (pb_id >= MAX_BEARERS)
-               return;
+       l = n->links[bearer_id].link;
+       if (!l)
+               return false;
+       rcv_nxt = l->rcv_nxt;
 
-       tnl = n->links[bearer_id].link;
-       if (!tnl)
-               return;
 
-       /* Ignore if duplicate */
-       if (less(oseqno, tnl->rcv_nxt))
-               return;
+       if (likely((state == SELF_UP_PEER_UP) && (usr != TUNNEL_PROTOCOL)))
+               return true;
 
-       pl = n->links[pb_id].link;
-       if (!pl)
-               return;
+       /* Find parallel link, if any */
+       for (i = 0; i < MAX_BEARERS; i++) {
+               if ((i != bearer_id) && n->links[i].link) {
+                       pl = n->links[i].link;
+                       break;
+               }
+       }
 
-       if (msg_type(hdr) == FAILOVER_MSG) {
-               if (tipc_link_is_up(pl)) {
-                       tipc_link_reset(pl);
+       /* Update node accesibility if applicable */
+       if (state == SELF_UP_PEER_COMING) {
+               if (!tipc_link_is_up(l))
+                       return true;
+               if (!msg_peer_link_is_up(hdr))
+                       return true;
+               tipc_node_fsm_evt(n, PEER_ESTABL_CONTACT_EVT);
+       }
+
+       if (state == SELF_DOWN_PEER_LEAVING) {
+               if (msg_peer_node_is_up(hdr))
+                       return false;
+               tipc_node_fsm_evt(n, PEER_LOST_CONTACT_EVT);
+       }
+
+       /* Ignore duplicate packets */
+       if (less(oseqno, rcv_nxt))
+               return true;
+
+       /* Initiate or update failover mode if applicable */
+       if ((usr == TUNNEL_PROTOCOL) && (mtyp == FAILOVER_MSG)) {
+               syncpt = oseqno + exp_pkts - 1;
+               if (pl && tipc_link_is_up(pl)) {
+                       tipc_node_link_down(n, pl->bearer_id);
                        pl->exec_mode = TIPC_LINK_BLOCKED;
                }
+               /* If pkts arrive out of order, use lowest calculated syncpt */
+               if (less(syncpt, n->sync_point))
+                       n->sync_point = syncpt;
+       }
+
+       /* Open parallel link when tunnel link reaches synch point */
+       if ((n->state == NODE_FAILINGOVER) && (more(rcv_nxt, n->sync_point))) {
+               tipc_node_fsm_evt(n, NODE_FAILOVER_END_EVT);
+               if (pl)
+                       pl->exec_mode = TIPC_LINK_OPEN;
+               return true;
+       }
+
+       /* Initiate or update synch mode if applicable */
+       if ((usr == TUNNEL_PROTOCOL) && (mtyp == SYNCH_MSG)) {
+               syncpt = iseqno + exp_pkts - 1;
+               if (n->state == SELF_UP_PEER_UP) {
+                       n->sync_point = syncpt;
+                       tipc_node_fsm_evt(n, NODE_SYNCH_BEGIN_EVT);
+               }
+               l->exec_mode = TIPC_LINK_TUNNEL;
+               if (less(syncpt, n->sync_point))
+                       n->sync_point = syncpt;
+       }
+
+       /* Open tunnel link when parallel link reaches synch point */
+       if ((n->state == NODE_SYNCHING) && (l->exec_mode == TIPC_LINK_TUNNEL)) {
+               if (pl)
+                       dlv_nxt = mod(pl->rcv_nxt - skb_queue_len(pl->inputq));
+               if (!pl || more(dlv_nxt, n->sync_point)) {
+                       tipc_node_fsm_evt(n, NODE_SYNCH_END_EVT);
+                       l->exec_mode = TIPC_LINK_OPEN;
+                       return true;
+               }
+               if ((usr == TUNNEL_PROTOCOL) && (mtyp == SYNCH_MSG))
+                       return true;
+               if (usr == LINK_PROTOCOL)
+                       return true;
+               return false;
        }
+       return true;
 }
 
 /**
@@ -921,12 +1102,11 @@ void tipc_rcv(struct net *net, struct sk_buff *skb, struct tipc_bearer *b)
 {
        struct sk_buff_head xmitq;
        struct tipc_node *n;
-       struct tipc_link *l;
-       struct tipc_msg *hdr;
-       struct tipc_media_addr *maddr;
+       struct tipc_msg *hdr = buf_msg(skb);
+       int usr = msg_user(hdr);
        int bearer_id = b->identity;
+       struct tipc_link_entry *le;
        int rc = 0;
-       int usr;
 
        __skb_queue_head_init(&xmitq);
 
@@ -935,8 +1115,6 @@ void tipc_rcv(struct net *net, struct sk_buff *skb, struct tipc_bearer *b)
                goto discard;
 
        /* Handle arrival of a non-unicast link packet */
-       hdr = buf_msg(skb);
-       usr = msg_user(hdr);
        if (unlikely(msg_non_seq(hdr))) {
                if (usr ==  LINK_CONFIG)
                        tipc_disc_rcv(net, skb, b);
@@ -949,42 +1127,41 @@ void tipc_rcv(struct net *net, struct sk_buff *skb, struct tipc_bearer *b)
        n = tipc_node_find(net, msg_prevnode(hdr));
        if (unlikely(!n))
                goto discard;
-       tipc_node_lock(n);
+       le = &n->links[bearer_id];
 
-       /* Prepare links for tunneled reception if applicable */
-       if (unlikely(usr == TUNNEL_PROTOCOL))
-               tipc_node_tnl_init(n, bearer_id, skb);
+       tipc_node_lock(n);
 
-       /* Locate link endpoint that should handle packet */
-       l = n->links[bearer_id].link;
-       if (unlikely(!l))
+       /* Is reception permitted at the moment ? */
+       if (!tipc_node_filter_pkt(n, hdr))
                goto unlock;
 
-       /* Is reception of this packet permitted at the moment ? */
-       if (unlikely(n->state != SELF_UP_PEER_UP))
-               if (!tipc_node_filter_skb(n, l, hdr))
-                       goto unlock;
-
-       if (unlikely(usr == LINK_PROTOCOL))
+       if (unlikely(msg_user(hdr) == LINK_PROTOCOL))
                tipc_bclink_sync_state(n, hdr);
 
        /* Release acked broadcast messages */
        if (unlikely(n->bclink.acked != msg_bcast_ack(hdr)))
                tipc_bclink_acknowledge(n, msg_bcast_ack(hdr));
 
-       /* Check protocol and update link state */
-       rc = tipc_link_rcv(l, skb, &xmitq);
+       /* Check and if necessary update node state */
+       if (likely(tipc_node_check_state(n, skb, bearer_id))) {
+               rc = tipc_link_rcv(le->link, skb, &xmitq);
+               skb = NULL;
+       }
 
        if (unlikely(rc & TIPC_LINK_UP_EVT))
-               tipc_node_link_up(n, bearer_id);
+               tipc_node_link_up(n, bearer_id, &xmitq);
+
        if (unlikely(rc & TIPC_LINK_DOWN_EVT))
-               tipc_link_reset(l);
-       skb = NULL;
+               tipc_node_link_down(n, bearer_id);
 unlock:
        tipc_node_unlock(n);
-       tipc_sk_rcv(net, &n->links[bearer_id].inputq);
-       maddr = &n->links[bearer_id].maddr;
-       tipc_bearer_xmit(net, bearer_id, &xmitq, maddr);
+
+       if (!skb_queue_empty(&le->inputq))
+               tipc_sk_rcv(net, &le->inputq);
+
+       if (!skb_queue_empty(&xmitq))
+               tipc_bearer_xmit(net, bearer_id, &xmitq, &le->maddr);
+
        tipc_node_put(n);
 discard:
        kfree_skb(skb);