/** Adds a GGEP block with the specified alternate locations to the output stream. */
static void addGGEP(OutputStream out, GGEPContainer ggep) throws IOException {
if (ggep == null || (ggep.locations.size() == 0 && ggep.createTime <= 0))
throw new NullPointerException("null or empty locations");
GGEP info = new GGEP();
if (ggep.locations.size() > 0) {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
try {
for (Iterator i = ggep.locations.iterator(); i.hasNext(); ) {
try {
Endpoint ep = (Endpoint) i.next();
baos.write(ep.getHostBytes());
ByteOrder.short2leb((short) ep.getPort(), baos);
} catch (UnknownHostException uhe) {
continue;
}
}
} catch (IOException impossible) {
ErrorService.error(impossible);
}
info.put(GGEP.GGEP_HEADER_ALTS, baos.toByteArray());
}
if (ggep.createTime > 0) info.put(GGEP.GGEP_HEADER_CREATE_TIME, ggep.createTime / 1000);
info.write(out);
}
/**
* @requires this and other have dotted-quad addresses, or names that can be resolved.
* @effects Returns true if this is on the same subnet as 'other', i.e., if this and other are in
* the same IP class and have the same network number.
*/
public boolean isSameSubnet(Endpoint other) {
byte[] a;
byte[] b;
int first;
try {
a = getHostBytes();
first = ByteOrder.ubyte2int(a[0]);
b = other.getHostBytes();
} catch (UnknownHostException e) {
return false;
}
// See http://www.3com.com/nsc/501302.html
// class A
if (first <= 127) return a[0] == b[0];
// class B
else if (first <= 191) return a[0] == b[0] && a[1] == b[1];
// class C
else return a[0] == b[0] && a[1] == b[1] && a[2] == b[2];
}
