/** "Remove matching deferred transmission entries." [DTN2] */
void remove_from_deferred(final Bundle bundle, int actions) {
ContactManager cm = BundleDaemon.getInstance().contactmgr();
cm.get_lock().lock();
try {
final LinkSet links = cm.links();
Iterator<Link> iter = links.iterator();
while (iter.hasNext()) {
Link link = iter.next();
// "a bundle might be deleted immediately after being loaded
// from storage, meaning that remove_from_deferred is called
// before the deferred list is created (since the link isn't
// fully set up yet). so just skip the link if there's no
// router info, and therefore no deferred list" [DTN2]
if (link.router_info() == null) {
continue;
}
DeferredList deferred = deferred_list(link);
ForwardingInfo info = deferred.find(bundle);
if (info != null) {
if ((info.action().getCode() & actions) > 0) {
Log.d(
TAG, String.format("removing bundle %s from link %s deferred list", bundle, link));
deferred.del(bundle);
}
}
}
} finally {
cm.get_lock().unlock();
}
}
/**
* "Called when the next hop link is available for transmission (i.e. either when it first arrives
* and the contact is brought up or when a bundle is completed and it's no longer busy).
*
* <p>Loops through the bundle list and calls fwd_to_matching on all bundles." [DTN2]
*/
protected void check_next_hop(Link next_hop) {
// "if the link isn't open, there's nothing to do now" [DTN2]
if (!next_hop.isopen()) {
Log.d(
TAG,
String.format(
"check_next_hop %s -> %s: link not open...", next_hop.name(), next_hop.nexthop()));
return;
}
// "if the link queue doesn't have space (based on the low water
// mark) don't do anything" [DTN2]
if (!next_hop.queue_has_space()) {
Log.d(
TAG,
String.format(
"check_next_hop %s -> %s: no space in queue...",
next_hop.name(), next_hop.nexthop()));
return;
}
Log.d(
TAG,
String.format(
"check_next_hop %s -> %s: checking deferred bundle list...",
next_hop.name(), next_hop.nexthop()));
// "because the loop below will remove the current bundle from
// the deferred list, invalidating any iterators pointing to its
// position, make sure to advance the iterator before processing
// the current bundle" [DTN2]
DeferredList deferred = deferred_list(next_hop);
deferred.list().get_lock().lock();
try {
Iterator<Bundle> iter = deferred.list().begin();
while (iter.hasNext()) {
if (next_hop.queue_is_full()) {
Log.d(
TAG,
String.format(
"check_next_hop %s: link queue is full, stopping loop", next_hop.name()));
break;
}
Bundle bundle = iter.next();
ForwardingInfo info = deferred.find(bundle);
assert info != null
: "TableBasedRouter: check_next_hop, ForwardingInfo regarding Bundle is null";
// "if should_fwd returns false, then the bundle was either
// already transmitted or is in flight on another node. since
// it's possible that one of the other transmissions will
// fail, we leave it on the deferred list for now, relying on
// the transmitted handlers to clean up the state" [DTN2]
if (!this.should_fwd(bundle, next_hop, info.action())) {
Log.d(TAG, String.format("check_next_hop: not forwarding to link %s", next_hop.name()));
continue;
}
// "if the link is available and not open, open it" [DTN2]
if (next_hop.isNotUnavailable() && (!next_hop.isopen()) && (!next_hop.isopening())) {
Log.d(
TAG,
String.format(
"check_next_hop: " + "opening %s because a message is intended for it",
next_hop.name()));
actions_.open_link(next_hop);
}
// "remove the bundle from the deferred list" [DTN2]
Log.d(
TAG,
String.format(
"check_next_hop: sending bundle %d to %s", bundle.bundleid(), next_hop.name()));
iter.remove();
actions_.queue_bundle(bundle, next_hop, info.action(), info.custody_spec());
}
} catch (BundleListLockNotHoldByCurrentThread e) {
Log.e(TAG, "Table Based Router " + e.toString());
} finally {
deferred.list().get_lock().unlock();
}
}