@Override
protected void handle_contact_down(ContactDownEvent event) {
Link link = event.contact().link();
assert (link != null) : "TableBasedRouter : handle_contact_down : link is null";
assert (!link.isdeleted()) : "TableBasedRouter : handle_contact_down : link is deleted";
// "if there are any bundles queued on the link when it goes down,
// schedule a timer to cancel those transmissions and reroute the
// bundles in case the link takes too long to come back up" [DTN2]
int num_queued = link.queue().size();
if (num_queued != 0) {
RerouteTimer reroute_timer = reroute_timers_.get(link.name());
if (reroute_timer == null) {
Log.d(
TAG,
String.format(
"link %s went down with %d bundles queued, "
+ "scheduling reroute timer in %d seconds",
link.name(), num_queued, link.params().potential_downtime()));
RerouteTimer t = new RerouteTimer(this, link);
t.schedule_in(link.params().potential_downtime());
reroute_timers_.put(link.name(), t);
}
}
}
@Override
protected void handle_contact_up(ContactUpEvent event) {
Link link = event.contact().link();
assert (link != null) : "TabledBasedRouter: handle_contact_up : link is null";
assert (!link.isdeleted()) : "TabledBasedRouter: handle_contact_up : link is deleted";
if (!link.isopen()) {
Log.e(
TAG,
String.format("contact up(link %s): event delivered but link not open", link.name()));
}
add_nexthop_route(link);
check_next_hop(link);
// "check if there's a pending reroute timer on the link, and if
// so, cancel it.
//
// note that there's a possibility that a link just bounces
// between up and down states but can't ever really send a bundle
// (or part of one), which we don't handle here since we can't
// distinguish that case from one in which the CL is actually
// sending data, just taking a long time to do so." [DTN2]
RerouteTimer reroute_timer = reroute_timers_.get(link.name());
if (reroute_timer != null) {
Log.d(TAG, String.format("link %s reopened, cancelling reroute timer", link.name()));
reroute_timers_.remove(link.name());
reroute_timer.cancel();
}
}
@Override
protected void handle_link_deleted(LinkDeletedEvent event) {
Link link = event.link();
assert (link != null) : "TableBasedRouter: handle_link_deleted: link is null";
route_table_.del_entries_for_nexthop(link);
RerouteTimer t = reroute_timers_.get(link.name());
if (t != null) {
Log.d(TAG, String.format("link %s deleted, cancelling reroute timer", link.name()));
reroute_timers_.remove(link.name());
t.cancel();
}
}
