tipc: simplify link supervision checkpointing
We change the sequence number checkpointing that is performed
by the timer in order to discover if the peer is active. Currently,
we store a checkpoint of the next expected sequence number "rcv_nxt"
at each timer expiration, and compare it to the current expected
number at next timeout expiration. Instead, we now use the already
existing field "silent_intv_cnt" for this task. We step the counter
at each timeout expiration, and zero it at each valid received packet.
If no valid packet has been received from the peer after "abort_limit"
number of silent timer intervals, the link is declared faulty and reset.
We also remove the multiple instances of timer activation from inside
the FSM function "link_state_event()", and now do it at only one place;
at the end of the timer function itself.
Reviewed-by: Erik Hugne <erik.hugne@ericsson.com>
Reviewed-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/tipc/link.c b/net/tipc/link.c
index c39543e..a5ea19e 100644
--- a/net/tipc/link.c
+++ b/net/tipc/link.c
@@ -86,7 +86,7 @@
*/
#define STARTING_EVT 856384768 /* link processing trigger */
#define TRAFFIC_MSG_EVT 560815u /* rx'd ??? */
-#define TIMEOUT_EVT 560817u /* link timer expired */
+#define SILENCE_EVT 560817u /* timer dicovered silence from peer */
/*
* State value stored in 'failover_pkts'
@@ -106,6 +106,7 @@
static void tipc_link_input(struct tipc_link *l, struct sk_buff *skb);
static bool tipc_data_input(struct tipc_link *l, struct sk_buff *skb);
static bool tipc_link_failover_rcv(struct tipc_link *l, struct sk_buff **skb);
+static void link_set_timer(struct tipc_link *link, unsigned long time);
/*
* Simple link routines
*/
@@ -197,11 +198,12 @@
}
/* do all other link processing performed on a periodic basis */
- link_state_event(l_ptr, TIMEOUT_EVT);
-
+ if (l_ptr->silent_intv_cnt || tipc_bclink_acks_missing(l_ptr->owner))
+ link_state_event(l_ptr, SILENCE_EVT);
+ l_ptr->silent_intv_cnt++;
if (skb_queue_len(&l_ptr->backlogq))
tipc_link_push_packets(l_ptr);
-
+ link_set_timer(l_ptr, l_ptr->keepalive_intv);
tipc_node_unlock(l_ptr->owner);
tipc_link_put(l_ptr);
}
@@ -261,7 +263,6 @@
/* note: peer i/f name is updated by reset/activate message */
memcpy(&l_ptr->media_addr, media_addr, sizeof(*media_addr));
l_ptr->owner = n_ptr;
- l_ptr->checkpoint = 1;
l_ptr->peer_session = INVALID_SESSION;
l_ptr->bearer_id = b_ptr->identity;
link_set_supervision_props(l_ptr, b_ptr->tolerance);
@@ -468,7 +469,6 @@
tipc_link_purge_backlog(l_ptr);
l_ptr->reasm_buf = NULL;
l_ptr->rcv_unacked = 0;
- l_ptr->checkpoint = 1;
l_ptr->snd_nxt = 1;
l_ptr->silent_intv_cnt = 0;
l_ptr->stale_count = 0;
@@ -481,6 +481,7 @@
link->rcv_nxt = 1;
link->stats.recv_info = 1;
+ link->silent_intv_cnt = 0;
tipc_node_link_up(node, link);
tipc_bearer_add_dest(node->net, link->bearer_id, link->addr);
}
@@ -501,45 +502,33 @@
if (!(l_ptr->flags & LINK_STARTED) && (event != STARTING_EVT))
return; /* Not yet. */
- if (l_ptr->flags & LINK_FAILINGOVER) {
- if (event == TIMEOUT_EVT)
- link_set_timer(l_ptr, timer_intv);
+ if (l_ptr->flags & LINK_FAILINGOVER)
return;
- }
switch (l_ptr->state) {
case WORKING_WORKING:
switch (event) {
case TRAFFIC_MSG_EVT:
case ACTIVATE_MSG:
+ l_ptr->silent_intv_cnt = 0;
break;
- case TIMEOUT_EVT:
- if (l_ptr->rcv_nxt != l_ptr->checkpoint) {
- l_ptr->checkpoint = l_ptr->rcv_nxt;
- if (tipc_bclink_acks_missing(l_ptr->owner)) {
+ case SILENCE_EVT:
+ if (!l_ptr->silent_intv_cnt) {
+ if (tipc_bclink_acks_missing(l_ptr->owner))
tipc_link_proto_xmit(l_ptr, STATE_MSG,
0, 0, 0, 0);
- l_ptr->silent_intv_cnt++;
- }
- link_set_timer(l_ptr, timer_intv);
break;
}
l_ptr->state = WORKING_UNKNOWN;
- l_ptr->silent_intv_cnt = 0;
tipc_link_proto_xmit(l_ptr, STATE_MSG, 1, 0, 0, 0);
- l_ptr->silent_intv_cnt++;
- link_set_timer(l_ptr, timer_intv);
break;
case RESET_MSG:
pr_debug("%s<%s>, requested by peer\n",
link_rst_msg, l_ptr->name);
tipc_link_reset(l_ptr);
l_ptr->state = RESET_RESET;
- l_ptr->silent_intv_cnt = 0;
tipc_link_proto_xmit(l_ptr, ACTIVATE_MSG,
0, 0, 0, 0);
- l_ptr->silent_intv_cnt++;
- link_set_timer(l_ptr, timer_intv);
break;
default:
pr_debug("%s%u in WW state\n", link_unk_evt, event);
@@ -551,46 +540,32 @@
case ACTIVATE_MSG:
l_ptr->state = WORKING_WORKING;
l_ptr->silent_intv_cnt = 0;
- link_set_timer(l_ptr, timer_intv);
break;
case RESET_MSG:
pr_debug("%s<%s>, requested by peer while probing\n",
link_rst_msg, l_ptr->name);
tipc_link_reset(l_ptr);
l_ptr->state = RESET_RESET;
- l_ptr->silent_intv_cnt = 0;
tipc_link_proto_xmit(l_ptr, ACTIVATE_MSG,
0, 0, 0, 0);
- l_ptr->silent_intv_cnt++;
- link_set_timer(l_ptr, timer_intv);
break;
- case TIMEOUT_EVT:
- if (l_ptr->rcv_nxt != l_ptr->checkpoint) {
+ case SILENCE_EVT:
+ if (!l_ptr->silent_intv_cnt) {
l_ptr->state = WORKING_WORKING;
- l_ptr->silent_intv_cnt = 0;
- l_ptr->checkpoint = l_ptr->rcv_nxt;
- if (tipc_bclink_acks_missing(l_ptr->owner)) {
+ if (tipc_bclink_acks_missing(l_ptr->owner))
tipc_link_proto_xmit(l_ptr, STATE_MSG,
0, 0, 0, 0);
- l_ptr->silent_intv_cnt++;
- }
- link_set_timer(l_ptr, timer_intv);
} else if (l_ptr->silent_intv_cnt <
l_ptr->abort_limit) {
tipc_link_proto_xmit(l_ptr, STATE_MSG,
1, 0, 0, 0);
- l_ptr->silent_intv_cnt++;
- link_set_timer(l_ptr, timer_intv);
} else { /* Link has failed */
pr_debug("%s<%s>, peer not responding\n",
link_rst_msg, l_ptr->name);
tipc_link_reset(l_ptr);
l_ptr->state = RESET_UNKNOWN;
- l_ptr->silent_intv_cnt = 0;
tipc_link_proto_xmit(l_ptr, RESET_MSG,
0, 0, 0, 0);
- l_ptr->silent_intv_cnt++;
- link_set_timer(l_ptr, timer_intv);
}
break;
default:
@@ -606,31 +581,22 @@
if (other && link_working_unknown(other))
break;
l_ptr->state = WORKING_WORKING;
- l_ptr->silent_intv_cnt = 0;
link_activate(l_ptr);
tipc_link_proto_xmit(l_ptr, STATE_MSG, 1, 0, 0, 0);
- l_ptr->silent_intv_cnt++;
if (l_ptr->owner->working_links == 1)
tipc_link_sync_xmit(l_ptr);
- link_set_timer(l_ptr, timer_intv);
break;
case RESET_MSG:
l_ptr->state = RESET_RESET;
- l_ptr->silent_intv_cnt = 0;
tipc_link_proto_xmit(l_ptr, ACTIVATE_MSG,
1, 0, 0, 0);
- l_ptr->silent_intv_cnt++;
- link_set_timer(l_ptr, timer_intv);
break;
case STARTING_EVT:
l_ptr->flags |= LINK_STARTED;
- l_ptr->silent_intv_cnt++;
link_set_timer(l_ptr, timer_intv);
break;
- case TIMEOUT_EVT:
+ case SILENCE_EVT:
tipc_link_proto_xmit(l_ptr, RESET_MSG, 0, 0, 0, 0);
- l_ptr->silent_intv_cnt++;
- link_set_timer(l_ptr, timer_intv);
break;
default:
pr_err("%s%u in RU state\n", link_unk_evt, event);
@@ -644,21 +610,16 @@
if (other && link_working_unknown(other))
break;
l_ptr->state = WORKING_WORKING;
- l_ptr->silent_intv_cnt = 0;
link_activate(l_ptr);
tipc_link_proto_xmit(l_ptr, STATE_MSG, 1, 0, 0, 0);
- l_ptr->silent_intv_cnt++;
if (l_ptr->owner->working_links == 1)
tipc_link_sync_xmit(l_ptr);
- link_set_timer(l_ptr, timer_intv);
break;
case RESET_MSG:
break;
- case TIMEOUT_EVT:
+ case SILENCE_EVT:
tipc_link_proto_xmit(l_ptr, ACTIVATE_MSG,
0, 0, 0, 0);
- l_ptr->silent_intv_cnt++;
- link_set_timer(l_ptr, timer_intv);
break;
default:
pr_err("%s%u in RR state\n", link_unk_evt, event);
@@ -1126,6 +1087,8 @@
skb = NULL;
goto unlock;
}
+ l_ptr->silent_intv_cnt = 0;
+
/* Synchronize with parallel link if applicable */
if (unlikely((l_ptr->flags & LINK_SYNCHING) && !msg_dup(msg))) {
if (!link_synch(l_ptr))
@@ -1295,8 +1258,8 @@
return;
}
- /* Record OOS packet arrival (force mismatch on next timeout) */
- l_ptr->checkpoint--;
+ /* Record OOS packet arrival */
+ l_ptr->silent_intv_cnt = 0;
/*
* Discard packet if a duplicate; otherwise add it to deferred queue
@@ -1480,7 +1443,7 @@
}
/* Record reception; force mismatch at next timeout: */
- l_ptr->checkpoint--;
+ l_ptr->silent_intv_cnt = 0;
link_state_event(l_ptr, TRAFFIC_MSG_EVT);
l_ptr->stats.recv_states++;