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tipc: Auto removal of peer down node instance
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A peer node is considered down if there are no
active links (or) lost contact to the node. In current implementation,
a peer node instance is deleted either if

a) TIPC module is removed (or)
b) Application can use a netlink/iproute2 interface to delete a
specific down node.

Thus, a down node instance lives in the system forever, unless the
application explicitly removes it.

We fix this by deleting the nodes which are down for
a specified amount of time (5 minutes).
Existing node supervision timer is used to achieve this.

Acked-by: Ying Xue <ying.xue@windriver.com>
Acked-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: GhantaKrishnamurthy MohanKrishna <mohan.krishna.ghanta.krishnamurthy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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@davem330
GhantaKrishnamurthy MohanKrishna authored and davem330 committed Jun 30, 2018
1 parent e397286 commit 6a939f3
Showing 1 changed file with 55 additions and 11 deletions.
66 changes: 55 additions & 11 deletions net/tipc/node.c
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Original file line number Diff line number Diff line change
Expand Up @@ -45,6 +45,7 @@
#include "netlink.h"

#define INVALID_NODE_SIG 0x10000
#define NODE_CLEANUP_AFTER 300000

/* Flags used to take different actions according to flag type
* TIPC_NOTIFY_NODE_DOWN: notify node is down
Expand Down Expand Up @@ -96,6 +97,7 @@ struct tipc_bclink_entry {
* @link_id: local and remote bearer ids of changing link, if any
* @publ_list: list of publications
* @rcu: rcu struct for tipc_node
* @delete_at: indicates the time for deleting a down node
*/
struct tipc_node {
u32 addr;
Expand All @@ -121,6 +123,7 @@ struct tipc_node {
unsigned long keepalive_intv;
struct timer_list timer;
struct rcu_head rcu;
unsigned long delete_at;
};

/* Node FSM states and events:
Expand Down Expand Up @@ -160,6 +163,7 @@ static struct tipc_node *tipc_node_find(struct net *net, u32 addr);
static struct tipc_node *tipc_node_find_by_id(struct net *net, u8 *id);
static void tipc_node_put(struct tipc_node *node);
static bool node_is_up(struct tipc_node *n);
static void tipc_node_delete_from_list(struct tipc_node *node);

struct tipc_sock_conn {
u32 port;
Expand Down Expand Up @@ -390,6 +394,7 @@ static struct tipc_node *tipc_node_create(struct net *net, u32 addr,
for (i = 0; i < MAX_BEARERS; i++)
spin_lock_init(&n->links[i].lock);
n->state = SELF_DOWN_PEER_LEAVING;
n->delete_at = jiffies + msecs_to_jiffies(NODE_CLEANUP_AFTER);
n->signature = INVALID_NODE_SIG;
n->active_links[0] = INVALID_BEARER_ID;
n->active_links[1] = INVALID_BEARER_ID;
Expand Down Expand Up @@ -433,11 +438,16 @@ static void tipc_node_calculate_timer(struct tipc_node *n, struct tipc_link *l)
tipc_link_set_abort_limit(l, tol / n->keepalive_intv);
}

static void tipc_node_delete(struct tipc_node *node)
static void tipc_node_delete_from_list(struct tipc_node *node)
{
list_del_rcu(&node->list);
hlist_del_rcu(&node->hash);
tipc_node_put(node);
}

static void tipc_node_delete(struct tipc_node *node)
{
tipc_node_delete_from_list(node);

del_timer_sync(&node->timer);
tipc_node_put(node);
Expand Down Expand Up @@ -544,6 +554,42 @@ void tipc_node_remove_conn(struct net *net, u32 dnode, u32 port)
tipc_node_put(node);
}

static void tipc_node_clear_links(struct tipc_node *node)
{
int i;

for (i = 0; i < MAX_BEARERS; i++) {
struct tipc_link_entry *le = &node->links[i];

if (le->link) {
kfree(le->link);
le->link = NULL;
node->link_cnt--;
}
}
}

/* tipc_node_cleanup - delete nodes that does not
* have active links for NODE_CLEANUP_AFTER time
*/
static int tipc_node_cleanup(struct tipc_node *peer)
{
struct tipc_net *tn = tipc_net(peer->net);
bool deleted = false;

spin_lock_bh(&tn->node_list_lock);
tipc_node_write_lock(peer);

if (!node_is_up(peer) && time_after(jiffies, peer->delete_at)) {
tipc_node_clear_links(peer);
tipc_node_delete_from_list(peer);
deleted = true;
}
tipc_node_write_unlock(peer);
spin_unlock_bh(&tn->node_list_lock);
return deleted;
}

/* tipc_node_timeout - handle expiration of node timer
*/
static void tipc_node_timeout(struct timer_list *t)
Expand All @@ -555,6 +601,12 @@ static void tipc_node_timeout(struct timer_list *t)
int bearer_id;
int rc = 0;

if (!node_is_up(n) && tipc_node_cleanup(n)) {
/*Removing the reference of Timer*/
tipc_node_put(n);
return;
}

__skb_queue_head_init(&xmitq);

for (bearer_id = 0; remains && (bearer_id < MAX_BEARERS); bearer_id++) {
Expand Down Expand Up @@ -1173,6 +1225,7 @@ static void node_lost_contact(struct tipc_node *n,
uint i;

pr_debug("Lost contact with %x\n", n->addr);
n->delete_at = jiffies + msecs_to_jiffies(NODE_CLEANUP_AFTER);

/* Clean up broadcast state */
tipc_bcast_remove_peer(n->net, n->bc_entry.link);
Expand Down Expand Up @@ -1742,7 +1795,6 @@ int tipc_nl_peer_rm(struct sk_buff *skb, struct genl_info *info)
struct tipc_node *peer;
u32 addr;
int err;
int i;

/* We identify the peer by its net */
if (!info->attrs[TIPC_NLA_NET])
Expand Down Expand Up @@ -1777,15 +1829,7 @@ int tipc_nl_peer_rm(struct sk_buff *skb, struct genl_info *info)
goto err_out;
}

for (i = 0; i < MAX_BEARERS; i++) {
struct tipc_link_entry *le = &peer->links[i];

if (le->link) {
kfree(le->link);
le->link = NULL;
peer->link_cnt--;
}
}
tipc_node_clear_links(peer);
tipc_node_write_unlock(peer);
tipc_node_delete(peer);

Expand Down

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