/**
* "Check whether the Bundle should be forwarded to the give route or not" [DTN2]
*
* @param bundle the Bundle to check
* @param route the route to check
*/
protected boolean should_fwd(final Bundle bundle, RouteEntry route) {
if (route == null) return false;
EndpointID prevhop = reception_cache_.lookup(bundle);
if (prevhop != null) {
if (prevhop.equals(route.link().remote_eid()) && !prevhop.equals(EndpointID.NULL_EID())) {
Log.d(
TAG,
String.format(
"should_fwd bundle %d: " + "skip %s since bundle arrived from the same node",
bundle.bundleid(), route.link().name()));
return false;
}
}
return super.should_fwd(bundle, route.link(), route.action());
}
/**
* "Check the route table entries that match the given bundle and have not already been found in
* the bundle history. If a match is found, call fwd_to_nexthop on it." [DTN2]
*
* @param bundle the bundle to forward
* @return "the number of links on which the bundle was queued (i.e. the number of matching route
* entries.)" [DTN2]
*/
protected int route_bundle(Bundle bundle) {
RouteEntryVec matches = new RouteEntryVec();
Log.d(TAG, String.format("route_bundle: checking bundle %d", bundle.bundleid()));
// "check to see if forwarding is suppressed to all nodes" [DTN2]
if (bundle
.fwdlog()
.get_count(
EndpointIDPattern.WILDCARD_EID(),
ForwardingInfo.state_t.SUPPRESSED.getCode(),
ForwardingInfo.ANY_ACTION)
> 0) {
Log.i(
TAG,
String.format(
"route_bundle: " + "ignoring bundle %d since forwarding is suppressed",
bundle.bundleid()));
return 0;
}
Link null_link = null;
route_table_.get_matching(bundle.dest(), null_link, matches);
// "sort the matching routes by priority, allowing subclasses to
// override the way in which the sorting occurs" [DTN2]
sort_routes(matches);
Log.d(
TAG,
String.format(
"route_bundle bundle id %d: checking %d route entry matches",
bundle.bundleid(), matches.size()));
int count = 0;
Iterator<RouteEntry> itr = matches.iterator();
while (itr.hasNext()) {
RouteEntry route = itr.next();
Log.d(
TAG,
String.format(
"checking route entry %s link %s (%s)",
route.toString(), route.link().name(), route.link()));
if (!should_fwd(bundle, route)) {
continue;
}
if (deferred_list(route.link()).list().contains(bundle)) {
Log.d(
TAG,
String.format(
"route_bundle bundle %d: " + "ignoring link %s since already deferred",
bundle.bundleid(), route.link().name()));
continue;
}
// "because there may be bundles that already have deferred
// transmission on the link, we first call check_next_hop to
// get them into the queue before trying to route the new
// arrival, otherwise it might leapfrog the other deferred
// bundles" [DTN2]
check_next_hop(route.link());
if (!fwd_to_nexthop(bundle, route)) {
continue;
}
++count;
}
Log.d(
TAG,
String.format(
"route_bundle bundle id %d: forwarded on %d links", bundle.bundleid(), count));
return count;
}
/** "Try to forward a bundle to a next hop route." [DTN2] */
protected boolean fwd_to_nexthop(Bundle bundle, RouteEntry route) {
Link link = route.link();
// "if the link is available and not open, open it" [DTN2]
if (link.isNotUnavailable() && (!link.isopen()) && (!link.isopening())) {
Log.d(TAG, String.format("opening %s because a message is intended for it", link.name()));
actions_.open_link(link);
}
// "if the link is open and has space in the queue, then queue the
// bundle for transmission there" [DTN2]
if (link.isopen() && !link.queue_is_full()) {
Log.d(TAG, String.format("queuing %d on %s", bundle.bundleid(), link.name()));
actions_.queue_bundle(bundle, link, route.action(), route.custody_spec());
return true;
}
// "otherwise we can't send the bundle now, so put it on the link's
// deferred list and log reason why we can't forward it" [DTN2]
DeferredList deferred = deferred_list(link);
if (!bundle.is_queued_on(deferred.list())) {
ForwardingInfo info =
new ForwardingInfo(
ForwardingInfo.state_t.NONE,
route.action(),
link.name_str(),
0xffffffff,
link.remote_eid(),
route.custody_spec());
deferred.add(bundle, info);
} else {
Log.w(
TAG,
String.format(
"bundle %d already exists on deferred list of link %s",
bundle.bundleid(), link.name()));
}
if (!link.isNotUnavailable()) {
Log.d(
TAG,
String.format(
"can't forward bundle %d to %s because link not available",
bundle.bundleid(), link.name()));
} else if (!link.isopen()) {
Log.d(
TAG,
String.format(
TAG,
"can't forward bundle %d to %s because link not open",
bundle.bundleid(),
link.name()));
} else if (link.queue_is_full()) {
Log.d(
TAG,
String.format(
TAG,
"can't forward bundle %d to %s because link queue is full",
bundle.bundleid(),
link.name()));
} else {
Log.d(TAG, String.format(TAG, "can't forward %d to %s", bundle.bundleid(), link.name()));
}
return false;
}