@Override
void processOFHello(OFHello m) throws IOException {
OFVersion theirVersion = m.getVersion();
OFVersion commonVersion = null;
/* First, check if there's a version bitmap supplied. WE WILL ALWAYS HAVE a controller-provided version bitmap. */
if (theirVersion.compareTo(OFVersion.OF_13) >= 0 && !m.getElements().isEmpty()) {
List<U32> bitmaps = new ArrayList<U32>();
List<OFHelloElem> elements = m.getElements();
/* Grab all bitmaps supplied */
for (OFHelloElem e : elements) {
if (e instanceof OFHelloElemVersionbitmap) {
bitmaps.addAll(((OFHelloElemVersionbitmap) e).getBitmaps());
} else {
log.warn("Unhandled OFHelloElem {}", e);
}
}
/* Lookup highest, common supported OpenFlow version */
commonVersion = computeOFVersionFromBitmap(bitmaps);
if (commonVersion == null) {
log.error(
"Could not negotiate common OpenFlow version for {} with greatest version bitmap algorithm.",
channel.remoteAddress());
channel.disconnect();
return;
} else {
log.info(
"Negotiated OpenFlow version of {} for {} with greatest version bitmap algorithm.",
commonVersion.toString(),
channel.remoteAddress());
factory = OFFactories.getFactory(commonVersion);
OFMessageDecoder decoder = pipeline.get(OFMessageDecoder.class);
decoder.setVersion(commonVersion);
}
}
/* If there's not a bitmap present, choose the lower of the two supported versions. */
else if (theirVersion.compareTo(factory.getVersion()) < 0) {
log.info(
"Negotiated down to switch OpenFlow version of {} for {} using lesser hello header algorithm.",
theirVersion.toString(),
channel.remoteAddress());
factory = OFFactories.getFactory(theirVersion);
OFMessageDecoder decoder = pipeline.get(OFMessageDecoder.class);
decoder.setVersion(theirVersion);
} /* else The controller's version is < or = the switch's, so keep original controller factory. */ else if (theirVersion
.equals(factory.getVersion())) {
log.info(
"Negotiated equal OpenFlow version of {} for {} using lesser hello header algorithm.",
factory.getVersion().toString(),
channel.remoteAddress());
} else {
log.info(
"Negotiated down to controller OpenFlow version of {} for {} using lesser hello header algorithm.",
factory.getVersion().toString(),
channel.remoteAddress());
}
setState(new WaitFeaturesReplyState());
}
