Added comments and unfold deep "if"-construct in timeout_handler

[tinc] / src / net.c

diff --git a/src/net.c b/src/net.c
index 52c7fe3..577b11f 100644 (file)
--- a/src/net.c
+++ b/src/net.c
@@ -42,6 +42,7 @@ static int sleeptime = 10;
 time_t last_config_check = 0;
 static timeout_t pingtimer;
 static timeout_t periodictimer;
+static struct timeval last_periodic_run_time;
 
 /* Purge edges and subnets of unreachable nodes. Use carefully. */
 
@@ -144,30 +145,76 @@ void terminate_connection(connection_t *c, bool report) {
   and close the connection.
 */
 static void timeout_handler(void *data) {
+
+       bool close_all_connections = false;
+
+       /*
+                timeout_handler will start after 30 seconds from start of tincd
+                hold information about the elapsed time since last time the handler
+                has been run
+       */
+       long sleep_time = now.tv_sec - last_periodic_run_time.tv_sec;
+       /*
+                It seems that finding sane default value is harder than expected
+                Since we send every second a UDP packet to make holepunching work
+                And default UDP state expire on firewalls is between 15-30 seconds
+                we drop all connections after 60 Seconds - UDPDiscoveryTimeout=30
+                by default
+       */
+       if (sleep_time > 2 * udp_discovery_timeout) {
+               logger(DEBUG_ALWAYS, LOG_ERR, "Awaking from dead after %ld seconds of sleep", sleep_time);
+               /*
+                       Do not send any packets to tinc after we wake up.
+                       The other node probably closed our connection but we still
+                       are holding context information to them. This may happen on
+                       laptops or any other hardware which can be suspended for some time.
+                       Sending any data to node that wasn't expecting it will produce
+                       annoying and misleading errors on the other side about failed signature
+                       verification and or about missing sptps context
+               */
+               close_all_connections = true;
+       }
+       last_periodic_run_time = now;
+
        for list_each(connection_t, c, connection_list) {
+               // control connections (eg. tinc ctl) do not have any timeout
                if(c->status.control)
                        continue;
 
-               if(c->last_ping_time + pingtimeout <= now.tv_sec) {
-                       if(c->edge) {
-                               try_tx(c->node, false);
-                               if(c->status.pinged) {
-                                       logger(DEBUG_CONNECTIONS, LOG_INFO, "%s (%s) didn't respond to PING in %ld seconds", c->name, c->hostname, (long)(now.tv_sec - c->last_ping_time));
-                               } else if(c->last_ping_time + pinginterval <= now.tv_sec) {
-                                       send_ping(c);
-                                       continue;
-                               } else {
-                                       continue;
-                               }
-                       } else {
-                               if(c->status.connecting)
-                                       logger(DEBUG_CONNECTIONS, LOG_WARNING, "Timeout while connecting to %s (%s)", c->name, c->hostname);
-                               else
-                                       logger(DEBUG_CONNECTIONS, LOG_WARNING, "Timeout from %s (%s) during authentication", c->name, c->hostname);
-                       }
+               if(close_all_connections) {
+                       logger(DEBUG_ALWAYS, LOG_ERR, "Forcing connection close after sleep time %s (%s)", c->name, c->hostname);
+                       terminate_connection(c, c->edge);
+                       continue;
+               }
+
+               // Bail out early if we haven't reached the ping timeout for this node yet
+               if(c->last_ping_time + pingtimeout > now.tv_sec)
+                       continue;
+
+               // timeout during connection establishing
+               if(!c->edge) {
+                       if(c->status.connecting)
+                               logger(DEBUG_CONNECTIONS, LOG_WARNING, "Timeout while connecting to %s (%s)", c->name, c->hostname);
+                       else
+                               logger(DEBUG_CONNECTIONS, LOG_WARNING, "Timeout from %s (%s) during authentication", c->name, c->hostname);
+
                        terminate_connection(c, c->edge);
+                       continue;
+               }
+
+               // helps in UDP holepunching
+               try_tx(c->node, false);
+
+               // timeout during ping
+               if(c->status.pinged) {
+                       logger(DEBUG_CONNECTIONS, LOG_INFO, "%s (%s) didn't respond to PING in %ld seconds", c->name, c->hostname, (long)now.tv_sec - c->last_ping_time);
+                       terminate_connection(c, c->edge);
+                       continue;
                }
 
+               // check whether we need to send a new ping
+               if(c->last_ping_time + pinginterval <= now.tv_sec)
+                       send_ping(c);
        }
 
        timeout_set(data, &(struct timeval){1, rand() % 100000});
@@ -457,6 +504,7 @@ void retry(void) {
   this is where it all happens...
 */
 int main_loop(void) {
+       last_periodic_run_time = now;
        timeout_add(&pingtimer, timeout_handler, &pingtimer, &(struct timeval){pingtimeout, rand() % 100000});
        timeout_add(&periodictimer, periodic_handler, &periodictimer, &(struct timeval){0, 0});