public boolean clean() {
Iterator it = names();
while (it.hasNext()) {
Name name;
try {
name = (Name) it.next();
} catch (ConcurrentModificationException e) {
return false;
}
Object[] elements = findExactSets(name);
for (int i = 0; i < elements.length; i++) {
Element element = (Element) elements[i];
if (element.expired()) removeSet(name, element.getType(), element);
}
}
return true;
}
/**
* Looks up Records in the Cache. This follows CNAMEs and handles negatively cached data.
*
* @param name The name to look up
* @param type The type to look up
* @param minCred The minimum acceptable credibility
* @return A SetResponse object
* @see SetResponse
* @see Credibility
*/
public SetResponse lookupRecords(Name name, short type, byte minCred) {
SetResponse cr = null;
boolean verbose = Options.check("verbosecache");
Object o = lookup(name, type);
if (verbose) logLookup(name, type, "Starting");
if (o == null || o == NXRRSET) {
/*
* The name exists, but the type was not found. Or, the
* name does not exist and no parent does either. Punt.
*/
if (verbose) logLookup(name, type, "no information found");
return SetResponse.ofType(SetResponse.UNKNOWN);
}
Object[] objects;
if (o instanceof Element) objects = new Object[] {o};
else objects = (Object[]) o;
int nelements = 0;
for (int i = 0; i < objects.length; i++) {
Element element = (Element) objects[i];
if (element.expired()) {
if (verbose) {
logLookup(name, type, element.toString());
logLookup(name, type, "expired: ignoring");
}
removeSet(name, type, element);
objects[i] = null;
} else if (element.credibility < minCred) {
if (verbose) {
logLookup(name, type, element.toString());
logLookup(name, type, "not credible: ignoring");
}
objects[i] = null;
} else {
nelements++;
}
}
if (nelements == 0) {
/* We have data, but can't use it. Punt. */
if (verbose) logLookup(name, type, "no useful data found");
return SetResponse.ofType(SetResponse.UNKNOWN);
}
/*
* We have something at the name. It could be the answer,
* a CNAME, DNAME, or NS, or a negative cache entry.
*
* Ignore wildcards, since it's pretty unlikely that any will be
* cached. The occasional extra query is easily balanced by the
* reduced number of lookups.
*/
for (int i = 0; i < objects.length; i++) {
if (objects[i] == null) continue;
Element element = (Element) objects[i];
if (verbose) logLookup(name, type, element.toString());
RRset rrset = null;
if (element instanceof PositiveElement) rrset = ((PositiveElement) element).rrset;
/* Is this a negatively cached entry? */
if (rrset == null) {
/*
* If this is an NXDOMAIN entry, return NXDOMAIN.
*/
if (element.getType() == 0) {
if (verbose) logLookup(name, type, "NXDOMAIN");
return SetResponse.ofType(SetResponse.NXDOMAIN);
}
/*
* If we're not looking for type ANY, return NXRRSET.
* Otherwise ignore this.
*/
if (type != Type.ANY) {
if (verbose) logLookup(name, type, "NXRRSET");
return SetResponse.ofType(SetResponse.NXRRSET);
} else {
if (verbose) logLookup(name, type, "ANY query; " + "ignoring NXRRSET");
continue;
}
}
short rtype = rrset.getType();
Name rname = rrset.getName();
if (name.equals(rname)) {
if (type != Type.CNAME && type != Type.ANY && rtype == Type.CNAME) {
if (verbose) logLookup(name, type, "cname");
return new SetResponse(SetResponse.CNAME, rrset);
} else if (type != Type.NS && type != Type.ANY && rtype == Type.NS) {
if (verbose) logLookup(name, type, "exact delegation");
return new SetResponse(SetResponse.DELEGATION, rrset);
} else {
if (verbose) logLookup(name, type, "exact match");
if (cr == null) cr = new SetResponse(SetResponse.SUCCESSFUL);
cr.addRRset(rrset);
}
} else if (name.subdomain(rname)) {
if (rtype == Type.DNAME) {
if (verbose) logLookup(name, type, "dname");
return new SetResponse(SetResponse.DNAME, rrset);
} else if (rtype == Type.NS) {
if (verbose) logLookup(name, type, "parent delegation");
return new SetResponse(SetResponse.DELEGATION, rrset);
} else {
if (verbose)
logLookup(name, type, "ignoring rrset (" + rname + " " + Type.string(rtype) + ")");
}
} else {
if (verbose)
logLookup(name, type, "ignoring rrset (" + rname + " " + Type.string(rtype) + ")");
}
}
/*
* As far as I can tell, the only legitimate time cr will be null is
* if we queried for ANY and only saw negative responses, but not an
* NXDOMAIN. Return UNKNOWN.
*/
if (cr == null && type == Type.ANY) return SetResponse.ofType(SetResponse.UNKNOWN);
else if (cr == null)
throw new IllegalStateException(
"looking up (" + name + " " + Type.string(type) + "): " + "cr == null.");
return cr;
}
