tipc: move protocol message sending away from link FSM
[cascardo/linux.git] / net / tipc / node.c
index 0b1d61a..9e20acf 100644 (file)
 #include "name_distr.h"
 #include "socket.h"
 #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);
+static void tipc_node_timeout(unsigned long data);
+static void tipc_node_fsm_evt(struct tipc_node *n, int evt);
 
 struct tipc_sock_conn {
        u32 port;
@@ -132,6 +160,7 @@ struct tipc_node *tipc_node_create(struct net *net, u32 addr)
        INIT_LIST_HEAD(&n_ptr->list);
        INIT_LIST_HEAD(&n_ptr->publ_list);
        INIT_LIST_HEAD(&n_ptr->conn_sks);
+       skb_queue_head_init(&n_ptr->bclink.namedq);
        __skb_queue_head_init(&n_ptr->bclink.deferdq);
        hlist_add_head_rcu(&n_ptr->hash, &tn->node_htable[tipc_hashfn(addr)]);
        list_for_each_entry_rcu(temp_node, &tn->node_list, list) {
@@ -139,14 +168,32 @@ struct tipc_node *tipc_node_create(struct net *net, u32 addr)
                        break;
        }
        list_add_tail_rcu(&n_ptr->list, &temp_node->list);
-       n_ptr->action_flags = TIPC_WAIT_PEER_LINKS_DOWN;
+       n_ptr->state = SELF_DOWN_PEER_LEAVING;
        n_ptr->signature = INVALID_NODE_SIG;
+       n_ptr->active_links[0] = INVALID_BEARER_ID;
+       n_ptr->active_links[1] = INVALID_BEARER_ID;
        tipc_node_get(n_ptr);
+       setup_timer(&n_ptr->timer, tipc_node_timeout, (unsigned long)n_ptr);
+       n_ptr->keepalive_intv = U32_MAX;
 exit:
        spin_unlock_bh(&tn->node_list_lock);
        return n_ptr;
 }
 
+static void tipc_node_calculate_timer(struct tipc_node *n, struct tipc_link *l)
+{
+       unsigned long tol = l->tolerance;
+       unsigned long intv = ((tol / 4) > 500) ? 500 : tol / 4;
+       unsigned long keepalive_intv = msecs_to_jiffies(intv);
+
+       /* Link with lowest tolerance determines timer interval */
+       if (keepalive_intv < n->keepalive_intv)
+               n->keepalive_intv = keepalive_intv;
+
+       /* Ensure link's abort limit corresponds to current interval */
+       l->abort_limit = l->tolerance / jiffies_to_msecs(n->keepalive_intv);
+}
+
 static void tipc_node_delete(struct tipc_node *node)
 {
        list_del_rcu(&node->list);
@@ -160,8 +207,11 @@ void tipc_node_stop(struct net *net)
        struct tipc_node *node, *t_node;
 
        spin_lock_bh(&tn->node_list_lock);
-       list_for_each_entry_safe(node, t_node, &tn->node_list, list)
+       list_for_each_entry_safe(node, t_node, &tn->node_list, list) {
+               if (del_timer(&node->timer))
+                       tipc_node_put(node);
                tipc_node_put(node);
+       }
        spin_unlock_bh(&tn->node_list_lock);
 }
 
@@ -219,131 +269,235 @@ void tipc_node_remove_conn(struct net *net, u32 dnode, u32 port)
        tipc_node_put(node);
 }
 
+/* tipc_node_timeout - handle expiration of node timer
+ */
+static void tipc_node_timeout(unsigned long data)
+{
+       struct tipc_node *n = (struct tipc_node *)data;
+       struct sk_buff_head xmitq;
+       struct tipc_link *l;
+       struct tipc_media_addr *maddr;
+       int bearer_id;
+       int rc = 0;
+
+       __skb_queue_head_init(&xmitq);
+
+       for (bearer_id = 0; bearer_id < MAX_BEARERS; bearer_id++) {
+               tipc_node_lock(n);
+               l = n->links[bearer_id].link;
+               if (l) {
+                       /* Link tolerance may change asynchronously: */
+                       tipc_node_calculate_timer(n, l);
+                       rc = tipc_link_timeout(l, &xmitq);
+                       if (rc & TIPC_LINK_DOWN_EVT)
+                               tipc_node_link_down(n, bearer_id);
+               }
+               tipc_node_unlock(n);
+               maddr = &n->links[bearer_id].maddr;
+               tipc_bearer_xmit(n->net, bearer_id, &xmitq, maddr);
+       }
+       if (!mod_timer(&n->timer, jiffies + n->keepalive_intv))
+               tipc_node_get(n);
+       tipc_node_put(n);
+}
+
 /**
  * tipc_node_link_up - handle addition of link
  *
  * Link becomes active (alone or shared) or standby, depending on its priority.
  */
-void tipc_node_link_up(struct tipc_node *n_ptr, struct tipc_link *l_ptr)
+static void tipc_node_link_up(struct tipc_node *n, int bearer_id,
+                             struct sk_buff_head *xmitq)
 {
-       struct tipc_link **active = &n_ptr->active_links[0];
+       int *slot0 = &n->active_links[0];
+       int *slot1 = &n->active_links[1];
+       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 = nl->peer_bearer_id << 16 | bearer_id;
 
-       n_ptr->working_links++;
-       n_ptr->action_flags |= TIPC_NOTIFY_LINK_UP;
-       n_ptr->link_id = l_ptr->peer_bearer_id << 16 | l_ptr->bearer_id;
+       /* Leave room for tunnel header when returning 'mtu' to users: */
+       n->links[bearer_id].mtu = nl->mtu - INT_H_SIZE;
 
-       pr_debug("Established link <%s> on network plane %c\n",
-                l_ptr->name, l_ptr->net_plane);
+       tipc_bearer_add_dest(n->net, bearer_id, n->addr);
 
-       if (!active[0]) {
-               active[0] = active[1] = l_ptr;
-               node_established_contact(n_ptr);
-               goto exit;
-       }
-       if (l_ptr->priority < active[0]->priority) {
-               pr_debug("New link <%s> becomes standby\n", l_ptr->name);
-               goto exit;
+       pr_debug("Established link <%s> on network plane %c\n",
+                nl->name, nl->net_plane);
+
+       /* 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;
        }
-       tipc_link_dup_queue_xmit(active[0], l_ptr);
-       if (l_ptr->priority == active[0]->priority) {
-               active[0] = l_ptr;
-               goto exit;
+
+       /* Second link => redistribute slots */
+       if (nl->priority > ol->priority) {
+               pr_debug("Old link <%s> becomes standby\n", ol->name);
+               *slot0 = bearer_id;
+               *slot1 = bearer_id;
+       } else if (nl->priority == ol->priority) {
+               *slot0 = bearer_id;
+       } else {
+               pr_debug("New link <%s> is standby\n", nl->name);
        }
-       pr_debug("Old link <%s> becomes standby\n", active[0]->name);
-       if (active[1] != active[0])
-               pr_debug("Old link <%s> becomes standby\n", active[1]->name);
-       active[0] = active[1] = l_ptr;
-exit:
-       /* Leave room for changeover header when returning 'mtu' to users: */
-       n_ptr->act_mtus[0] = active[0]->mtu - INT_H_SIZE;
-       n_ptr->act_mtus[1] = active[1]->mtu - INT_H_SIZE;
+
+       /* Prepare synchronization with first link */
+       tipc_link_tnl_prepare(ol, nl, SYNCH_MSG, xmitq);
 }
 
 /**
- * node_select_active_links - select active link
+ * tipc_node_link_down - handle loss of link
  */
-static void node_select_active_links(struct tipc_node *n_ptr)
+static void tipc_node_link_down(struct tipc_node *n, int bearer_id)
 {
-       struct tipc_link **active = &n_ptr->active_links[0];
-       u32 i;
-       u32 highest_prio = 0;
+       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, *tnl;
+       struct sk_buff_head xmitq;
+
+       l = n->links[bearer_id].link;
+       if (!l || !tipc_link_is_up(l))
+               return;
 
-       active[0] = active[1] = NULL;
+       __skb_queue_head_init(&xmitq);
 
-       for (i = 0; i < MAX_BEARERS; i++) {
-               struct tipc_link *l_ptr = n_ptr->links[i];
+       n->working_links--;
+       n->action_flags |= TIPC_NOTIFY_LINK_DOWN;
+       n->link_id = l->peer_bearer_id << 16 | bearer_id;
 
-               if (!l_ptr || !tipc_link_is_up(l_ptr) ||
-                   (l_ptr->priority < highest_prio))
-                       continue;
+       tipc_bearer_remove_dest(n->net, l->bearer_id, n->addr);
 
-               if (l_ptr->priority > highest_prio) {
-                       highest_prio = l_ptr->priority;
-                       active[0] = active[1] = l_ptr;
-               } else {
-                       active[1] = l_ptr;
+       pr_debug("Lost link <%s> on network plane %c\n",
+                l->name, l->net_plane);
+
+       /* Select new active link if any available */
+       *slot0 = INVALID_BEARER_ID;
+       *slot1 = INVALID_BEARER_ID;
+       for (i = 0; i < MAX_BEARERS; i++) {
+               _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) {
+                       highest = _l->priority;
+                       *slot0 = i;
+                       *slot1 = i;
+                       continue;
                }
+               *slot1 = i;
+       }
+
+       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);
 }
 
-/**
- * tipc_node_link_down - handle loss of link
- */
-void tipc_node_link_down(struct tipc_node *n_ptr, struct tipc_link *l_ptr)
+bool tipc_node_is_up(struct tipc_node *n)
 {
-       struct tipc_net *tn = net_generic(n_ptr->net, tipc_net_id);
-       struct tipc_link **active;
+       return n->active_links[0] != INVALID_BEARER_ID;
+}
 
-       n_ptr->working_links--;
-       n_ptr->action_flags |= TIPC_NOTIFY_LINK_DOWN;
-       n_ptr->link_id = l_ptr->peer_bearer_id << 16 | l_ptr->bearer_id;
+void tipc_node_check_dest(struct tipc_node *n, struct tipc_bearer *b,
+                         bool *link_up, bool *addr_match,
+                         struct tipc_media_addr *maddr)
+{
+       struct tipc_link *l = n->links[b->identity].link;
+       struct tipc_media_addr *curr = &n->links[b->identity].maddr;
 
-       if (!tipc_link_is_active(l_ptr)) {
-               pr_debug("Lost standby link <%s> on network plane %c\n",
-                        l_ptr->name, l_ptr->net_plane);
-               return;
-       }
-       pr_debug("Lost link <%s> on network plane %c\n",
-                l_ptr->name, l_ptr->net_plane);
-
-       active = &n_ptr->active_links[0];
-       if (active[0] == l_ptr)
-               active[0] = active[1];
-       if (active[1] == l_ptr)
-               active[1] = active[0];
-       if (active[0] == l_ptr)
-               node_select_active_links(n_ptr);
-       if (tipc_node_is_up(n_ptr))
-               tipc_link_failover_send_queue(l_ptr);
-       else
-               node_lost_contact(n_ptr);
-
-       /* Leave room for changeover header when returning 'mtu' to users: */
-       if (active[0]) {
-               n_ptr->act_mtus[0] = active[0]->mtu - INT_H_SIZE;
-               n_ptr->act_mtus[1] = active[1]->mtu - INT_H_SIZE;
-               return;
-       }
-       /* Loopback link went down? No fragmentation needed from now on. */
-       if (n_ptr->addr == tn->own_addr) {
-               n_ptr->act_mtus[0] = MAX_MSG_SIZE;
-               n_ptr->act_mtus[1] = MAX_MSG_SIZE;
+       *link_up = l && tipc_link_is_up(l);
+       *addr_match = l && !memcmp(curr, maddr, sizeof(*maddr));
+}
+
+bool tipc_node_update_dest(struct tipc_node *n,  struct tipc_bearer *b,
+                          struct tipc_media_addr *maddr)
+{
+       struct tipc_link *l = n->links[b->identity].link;
+       struct tipc_media_addr *curr = &n->links[b->identity].maddr;
+       struct sk_buff_head *inputq = &n->links[b->identity].inputq;
+
+       if (!l) {
+               l = tipc_link_create(n, b, maddr, inputq, &n->bclink.namedq);
+               if (!l)
+                       return false;
+               tipc_node_calculate_timer(n, l);
+               if (n->link_cnt == 1) {
+                       if (!mod_timer(&n->timer, jiffies + n->keepalive_intv))
+                               tipc_node_get(n);
+               }
        }
+       memcpy(&l->media_addr, maddr, sizeof(*maddr));
+       memcpy(curr, maddr, sizeof(*maddr));
+       tipc_node_link_down(n, b->identity);
+       return true;
 }
 
-int tipc_node_active_links(struct tipc_node *n_ptr)
+void tipc_node_delete_links(struct net *net, int bearer_id)
 {
-       return n_ptr->active_links[0] != NULL;
+       struct tipc_net *tn = net_generic(net, tipc_net_id);
+       struct tipc_link *l;
+       struct tipc_node *n;
+
+       rcu_read_lock();
+       list_for_each_entry_rcu(n, &tn->node_list, list) {
+               tipc_node_lock(n);
+               l = n->links[bearer_id].link;
+               if (l) {
+                       tipc_node_link_down(n, bearer_id);
+                       n->links[bearer_id].link = NULL;
+                       n->link_cnt--;
+               }
+               tipc_node_unlock(n);
+               kfree(l);
+       }
+       rcu_read_unlock();
 }
 
-int tipc_node_is_up(struct tipc_node *n_ptr)
+static void tipc_node_reset_links(struct tipc_node *n)
 {
-       return tipc_node_active_links(n_ptr);
+       char addr_string[16];
+       u32 i;
+
+       tipc_node_lock(n);
+
+       pr_warn("Resetting all links to %s\n",
+               tipc_addr_string_fill(addr_string, n->addr));
+
+       for (i = 0; i < MAX_BEARERS; i++) {
+               if (!n->links[i].link)
+                       continue;
+               tipc_node_link_down(n, i);
+       }
+       tipc_node_unlock(n);
 }
 
 void tipc_node_attach_link(struct tipc_node *n_ptr, struct tipc_link *l_ptr)
 {
-       n_ptr->links[l_ptr->bearer_id] = l_ptr;
+       n_ptr->links[l_ptr->bearer_id].link = l_ptr;
        n_ptr->link_cnt++;
 }
 
@@ -352,15 +506,211 @@ void tipc_node_detach_link(struct tipc_node *n_ptr, struct tipc_link *l_ptr)
        int i;
 
        for (i = 0; i < MAX_BEARERS; i++) {
-               if (l_ptr != n_ptr->links[i])
+               if (l_ptr != n_ptr->links[i].link)
                        continue;
-               n_ptr->links[i] = NULL;
+               n_ptr->links[i].link = NULL;
                n_ptr->link_cnt--;
        }
 }
 
+/* tipc_node_fsm_evt - node finite state machine
+ * Determines when contact is allowed with peer node
+ */
+static void tipc_node_fsm_evt(struct tipc_node *n, int evt)
+{
+       int state = n->state;
+
+       switch (state) {
+       case SELF_DOWN_PEER_DOWN:
+               switch (evt) {
+               case SELF_ESTABL_CONTACT_EVT:
+                       state = SELF_UP_PEER_COMING;
+                       break;
+               case PEER_ESTABL_CONTACT_EVT:
+                       state = SELF_COMING_PEER_UP;
+                       break;
+               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:
+                       goto illegal_evt;
+               }
+               break;
+       case SELF_UP_PEER_UP:
+               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_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:
+                       goto illegal_evt;
+               }
+               break;
+       case SELF_DOWN_PEER_LEAVING:
+               switch (evt) {
+               case PEER_LOST_CONTACT_EVT:
+                       state = SELF_DOWN_PEER_DOWN;
+                       break;
+               case SELF_ESTABL_CONTACT_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:
+                       goto illegal_evt;
+               }
+               break;
+       case SELF_UP_PEER_COMING:
+               switch (evt) {
+               case PEER_ESTABL_CONTACT_EVT:
+                       state = SELF_UP_PEER_UP;
+                       break;
+               case SELF_LOST_CONTACT_EVT:
+                       state = SELF_DOWN_PEER_LEAVING;
+                       break;
+               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:
+                       goto illegal_evt;
+               }
+               break;
+       case SELF_COMING_PEER_UP:
+               switch (evt) {
+               case SELF_ESTABL_CONTACT_EVT:
+                       state = SELF_UP_PEER_UP;
+                       break;
+               case PEER_LOST_CONTACT_EVT:
+                       state = SELF_LEAVING_PEER_DOWN;
+                       break;
+               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:
+                       goto illegal_evt;
+               }
+               break;
+       case SELF_LEAVING_PEER_DOWN:
+               switch (evt) {
+               case SELF_LOST_CONTACT_EVT:
+                       state = SELF_DOWN_PEER_DOWN;
+                       break;
+               case SELF_ESTABL_CONTACT_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:
+                       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_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_LEAVING_PEER_DOWN)
+               return false;
+
+       if (state == SELF_DOWN_PEER_LEAVING) {
+               if (msg_peer_node_is_up(hdr))
+                       return false;
+       }
+
+       return true;
+}
+
 static void node_established_contact(struct tipc_node *n_ptr)
 {
+       tipc_node_fsm_evt(n_ptr, SELF_ESTABL_CONTACT_EVT);
        n_ptr->action_flags |= TIPC_NOTIFY_NODE_UP;
        n_ptr->bclink.oos_state = 0;
        n_ptr->bclink.acked = tipc_bclink_get_last_sent(n_ptr->net);
@@ -396,21 +746,16 @@ static void node_lost_contact(struct tipc_node *n_ptr)
 
        /* Abort any ongoing link failover */
        for (i = 0; i < MAX_BEARERS; i++) {
-               struct tipc_link *l_ptr = n_ptr->links[i];
+               struct tipc_link *l_ptr = n_ptr->links[i].link;
                if (!l_ptr)
                        continue;
-               l_ptr->flags &= ~LINK_FAILINGOVER;
-               l_ptr->failover_checkpt = 0;
-               l_ptr->failover_pkts = 0;
-               kfree_skb(l_ptr->failover_skb);
-               l_ptr->failover_skb = NULL;
+               l_ptr->exec_mode = TIPC_LINK_OPEN;
+               kfree_skb(l_ptr->failover_reasm_skb);
+               l_ptr->failover_reasm_skb = NULL;
                tipc_link_reset_fragments(l_ptr);
        }
-
-       n_ptr->action_flags &= ~TIPC_WAIT_OWN_LINKS_DOWN;
-
        /* Prevent re-contact with node until cleanup is done */
-       n_ptr->action_flags |= TIPC_WAIT_PEER_LINKS_DOWN;
+       tipc_node_fsm_evt(n_ptr, SELF_LOST_CONTACT_EVT);
 
        /* Notify publications from this node */
        n_ptr->action_flags |= TIPC_NOTIFY_NODE_DOWN;
@@ -453,7 +798,7 @@ int tipc_node_get_linkname(struct net *net, u32 bearer_id, u32 addr,
                goto exit;
 
        tipc_node_lock(node);
-       link = node->links[bearer_id];
+       link = node->links[bearer_id].link;
        if (link) {
                strncpy(linkname, link->name, len);
                err = 0;
@@ -522,7 +867,7 @@ void tipc_node_unlock(struct tipc_node *node)
                tipc_bclink_input(net);
 
        if (flags & TIPC_BCAST_RESET)
-               tipc_link_reset_all(node);
+               tipc_node_reset_links(node);
 }
 
 /* Caller should hold node lock for the passed node */
@@ -559,6 +904,269 @@ msg_full:
        return -EMSGSIZE;
 }
 
+static struct tipc_link *tipc_node_select_link(struct tipc_node *n, int sel,
+                                              int *bearer_id,
+                                              struct tipc_media_addr **maddr)
+{
+       int id = n->active_links[sel & 1];
+
+       if (unlikely(id < 0))
+               return NULL;
+
+       *bearer_id = id;
+       *maddr = &n->links[id].maddr;
+       return n->links[id].link;
+}
+
+/**
+ * tipc_node_xmit() is the general link level function for message sending
+ * @net: the applicable net namespace
+ * @list: chain of buffers containing message
+ * @dnode: address of destination node
+ * @selector: a number used for deterministic link selection
+ * Consumes the buffer chain, except when returning -ELINKCONG
+ * Returns 0 if success, otherwise errno: -ELINKCONG,-EHOSTUNREACH,-EMSGSIZE
+ */
+int tipc_node_xmit(struct net *net, struct sk_buff_head *list,
+                  u32 dnode, int selector)
+{
+       struct tipc_link *l = NULL;
+       struct tipc_node *n;
+       struct sk_buff_head xmitq;
+       struct tipc_media_addr *maddr;
+       int bearer_id;
+       int rc = -EHOSTUNREACH;
+
+       __skb_queue_head_init(&xmitq);
+       n = tipc_node_find(net, dnode);
+       if (likely(n)) {
+               tipc_node_lock(n);
+               l = tipc_node_select_link(n, selector, &bearer_id, &maddr);
+               if (likely(l))
+                       rc = tipc_link_xmit(l, list, &xmitq);
+               if (unlikely(rc == -ENOBUFS))
+                       tipc_node_link_down(n, bearer_id);
+               tipc_node_unlock(n);
+               tipc_node_put(n);
+       }
+       if (likely(!rc)) {
+               tipc_bearer_xmit(net, bearer_id, &xmitq, maddr);
+               return 0;
+       }
+       if (likely(in_own_node(net, dnode))) {
+               tipc_sk_rcv(net, list);
+               return 0;
+       }
+       return rc;
+}
+
+/* tipc_node_xmit_skb(): send single buffer to destination
+ * Buffers sent via this functon are generally TIPC_SYSTEM_IMPORTANCE
+ * messages, which will not be rejected
+ * The only exception is datagram messages rerouted after secondary
+ * lookup, which are rare and safe to dispose of anyway.
+ * TODO: Return real return value, and let callers use
+ * tipc_wait_for_sendpkt() where applicable
+ */
+int tipc_node_xmit_skb(struct net *net, struct sk_buff *skb, u32 dnode,
+                      u32 selector)
+{
+       struct sk_buff_head head;
+       int rc;
+
+       skb_queue_head_init(&head);
+       __skb_queue_tail(&head, skb);
+       rc = tipc_node_xmit(net, &head, dnode, selector);
+       if (rc == -ELINKCONG)
+               kfree_skb(skb);
+       return 0;
+}
+
+/**
+ * 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 bool tipc_node_check_state(struct tipc_node *n, struct sk_buff *skb,
+                                 int bearer_id)
+{
+       struct tipc_msg *hdr = buf_msg(skb);
+       int usr = msg_user(hdr);
+       int mtyp = msg_type(hdr);
+       u16 oseqno = msg_seqno(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;
+
+       l = n->links[bearer_id].link;
+       if (!l)
+               return false;
+       rcv_nxt = l->rcv_nxt;
+
+
+       if (likely((state == SELF_UP_PEER_UP) && (usr != TUNNEL_PROTOCOL)))
+               return true;
+
+       /* 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;
+               }
+       }
+
+       /* 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;
+}
+
+/**
+ * tipc_rcv - process TIPC packets/messages arriving from off-node
+ * @net: the applicable net namespace
+ * @skb: TIPC packet
+ * @bearer: pointer to bearer message arrived on
+ *
+ * Invoked with no locks held. Bearer pointer must point to a valid bearer
+ * structure (i.e. cannot be NULL), but bearer can be inactive.
+ */
+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_msg *hdr = buf_msg(skb);
+       int usr = msg_user(hdr);
+       int bearer_id = b->identity;
+       struct tipc_link_entry *le;
+       int rc = 0;
+
+       __skb_queue_head_init(&xmitq);
+
+       /* Ensure message is well-formed */
+       if (unlikely(!tipc_msg_validate(skb)))
+               goto discard;
+
+       /* Handle arrival of a non-unicast link packet */
+       if (unlikely(msg_non_seq(hdr))) {
+               if (usr ==  LINK_CONFIG)
+                       tipc_disc_rcv(net, skb, b);
+               else
+                       tipc_bclink_rcv(net, skb);
+               return;
+       }
+
+       /* Locate neighboring node that sent packet */
+       n = tipc_node_find(net, msg_prevnode(hdr));
+       if (unlikely(!n))
+               goto discard;
+       le = &n->links[bearer_id];
+
+       tipc_node_lock(n);
+
+       /* Is reception permitted at the moment ? */
+       if (!tipc_node_filter_pkt(n, hdr))
+               goto unlock;
+
+       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 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, &xmitq);
+
+       if (unlikely(rc & TIPC_LINK_DOWN_EVT))
+               tipc_node_link_down(n, bearer_id);
+unlock:
+       tipc_node_unlock(n);
+
+       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);
+}
+
 int tipc_nl_node_dump(struct sk_buff *skb, struct netlink_callback *cb)
 {
        int err;