Add a function to manually start the connection timeout timers.

If the application knows the peer is offline, it can call utcp_offline().
This will start the connection timers on all connections to that peer.
This can be undone by marking the peer online again. This will also reset
the retransmission timers.

diff --git a/utcp.c b/utcp.c
index f4bd7cf718c19197c00ad14efb1b322275a21739..d837d27a1b96fe05b860ce8fcf692bbda115f092 100644 (file)
--- a/utcp.c
+++ b/utcp.c
@@ -1863,9 +1863,15 @@ void utcp_reset_timers(struct utcp *utcp) {
        then.tv_sec += utcp->timeout;
 
        for(int i = 0; i < utcp->nconnections; i++) {
-               utcp->connections[i]->rtrx_timeout = now;
-               utcp->connections[i]->conn_timeout = then;
-               utcp->connections[i]->rtt_start.tv_sec = 0;
+               struct utcp_connection *c = utcp->connections[i];
+
+               if(c->reapable) {
+                       continue;
+               }
+
+               c->rtrx_timeout = now;
+               c->conn_timeout = then;
+               c->rtt_start.tv_sec = 0;
        }
 
        if(utcp->rto > START_RTO) {
@@ -1990,3 +1996,48 @@ void utcp_set_accept_cb(struct utcp *utcp, utcp_accept_t accept, utcp_pre_accept
                utcp->pre_accept = pre_accept;
        }
 }
+
+void utcp_expect_data(struct utcp_connection *c, bool expect) {
+       if(!c || c->reapable) {
+               return;
+       }
+
+       if(!(c->state == ESTABLISHED || c->state == FIN_WAIT_1 || c->state == FIN_WAIT_2)) {
+               return;
+       }
+
+       if(expect) {
+               // If we expect data, start the connection timer.
+               if(!timerisset(&c->conn_timeout)) {
+                       gettimeofday(&c->conn_timeout, NULL);
+                       c->conn_timeout.tv_sec += c->utcp->timeout;
+               }
+       } else {
+               // If we want to cancel expecting data, only clear the timer when there is no unACKed data.
+               if(c->snd.una == c->snd.last) {
+                       timerclear(&c->conn_timeout);
+               }
+       }
+}
+
+void utcp_offline(struct utcp *utcp, bool offline) {
+       for(int i = 0; i < utcp->nconnections; i++) {
+               struct utcp_connection *c = utcp->connections[i];
+
+               if(!c->reapable) {
+                       utcp_expect_data(c, offline);
+
+                       // If we are online again, reset the retransmission timers, but keep the connection timeout as it is,
+                       // to prevent peers toggling online/offline state frequently from keeping connections alive
+                       // if there is no progress in sending actual data.
+                       if(!offline) {
+                               gettimeofday(&utcp->connections[i]->rtrx_timeout, NULL);
+                               utcp->connections[i]->rtt_start.tv_sec = 0;
+                       }
+               }
+       }
+
+       if(!offline && utcp->rto > START_RTO) {
+               utcp->rto = START_RTO;
+       }
+}

diff --git a/utcp.h b/utcp.h
index 5d646762437cafe093796d787d78ee45bd0e5532..4b7075b56520eb79e4c3600ed7ca6427d0421b56 100644 (file)
--- a/utcp.h
+++ b/utcp.h
@@ -89,6 +89,8 @@ extern void utcp_set_mtu(struct utcp *utcp, uint16_t mtu);
 
 extern void utcp_reset_timers(struct utcp *utcp);
 
+extern void utcp_offline(struct utcp *utcp, bool offline);
+
 // Per-socket options
 
 extern size_t utcp_get_sndbuf(struct utcp_connection *connection);
@@ -110,4 +112,6 @@ extern void utcp_set_keepalive(struct utcp_connection *connection, bool keepaliv
 
 extern size_t utcp_get_outq(struct utcp_connection *connection);
 
+extern void utcp_expect_data(struct utcp_connection *connection, bool expect);
+
 #endif