/**
* Determine the highest supported version of OpenFlow in common between both our OFVersion bitmap
* and the switch's.
*
* @param theirs, the version bitmaps of the switch
* @return the highest OFVersion in common b/t the two
*/
private OFVersion computeOFVersionFromBitmap(List<U32> theirs) {
Iterator<U32> theirsItr = theirs.iterator();
Iterator<U32> oursItr = ofBitmaps.iterator();
OFVersion version = null;
int pos = 0;
int size = 32;
while (theirsItr.hasNext() && oursItr.hasNext()) {
int t = theirsItr.next().getRaw();
int o = oursItr.next().getRaw();
int common = t & o; /* Narrow down the results to the common bits */
for (int i = 0; i < size; i++) {
/* Iterate over and locate the 1's */
int tmp = common & (1 << i); /* Select the bit of interest, 0-31 */
if (tmp != 0) {
/* Is the version of this bit in common? */
for (OFVersion v : OFVersion.values()) {
/* Which version does this bit represent? */
if (v.getWireVersion() == i + (size * pos)) {
version = v;
}
}
}
}
pos++; /* OFVersion position. 1-31 = 1, 32 - 63 = 2, etc. Inc at end so it starts at 0. */
}
return version;
}
@Override
void processOFHello(OFHello m) throws IOException {
OFVersion version = m.getVersion();
/* Choose the lower of the two supported versions. */
if (version.compareTo(factory.getVersion()) < 0) {
factory = OFFactories.getFactory(version);
} /* else The controller's version is < or = the switch's, so keep original controller factory. */
OFMessageDecoder decoder = pipeline.get(OFMessageDecoder.class);
decoder.setVersion(version);
setState(new WaitFeaturesReplyState());
}
@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());
}