/**
* Deserialize an IGMP message.
*
* @param data bytes to deserialize
* @param offset offset to start deserializing from
* @param length length of the data to deserialize
* @return populated IGMP object
*/
@Override
public IPacket deserialize(final byte[] data, final int offset, final int length) {
final IGMP igmp;
try {
igmp = IGMP.deserializer().deserialize(data, offset, length);
} catch (DeserializationException e) {
log.error("Deserialization exception", e);
return this;
}
this.igmpType = igmp.igmpType;
this.resField = igmp.resField;
this.checksum = igmp.checksum;
this.groups = igmp.groups;
return this;
}
/**
* Deserializer function for IPv4 packets.
*
* @return deserializer function
*/
public static Deserializer<IGMP> deserializer() {
return (data, offset, length) -> {
checkInput(data, offset, length, IGMPv2.HEADER_LENGTH);
// we will assume that this is IGMPv2 if the length is 8
boolean isV2 = length == IGMPv2.HEADER_LENGTH;
IGMP igmp = isV2 ? new IGMPv2() : new IGMPv3();
final ByteBuffer bb = ByteBuffer.wrap(data, offset, length);
igmp.igmpType = bb.get();
igmp.resField = bb.get();
igmp.checksum = bb.getShort();
if (isV2) {
igmp.addGroup(new IGMPQuery(IpAddress.valueOf(bb.getInt()), 0));
if (igmp.validChecksum()) {
return igmp;
}
throw new DeserializationException("invalid checksum");
}
// second check for IGMPv3
checkInput(data, offset, length, IGMPv3.MINIMUM_HEADER_LEN);
String msg;
switch (igmp.igmpType) {
case TYPE_IGMPV3_MEMBERSHIP_QUERY:
IGMPQuery qgroup = new IGMPQuery();
qgroup.deserialize(bb);
igmp.groups.add(qgroup);
break;
case TYPE_IGMPV3_MEMBERSHIP_REPORT:
bb.getShort(); // Ignore resvd
int ngrps = bb.getShort();
for (; ngrps > 0; ngrps--) {
IGMPMembership mgroup = new IGMPMembership();
mgroup.deserialize(bb);
igmp.groups.add(mgroup);
}
break;
/*
* NOTE: according to the IGMPv3 spec. These previous IGMP type fields
* must be supported. At this time we are going to <b>assume</b> we run
* in a modern network where all devices are IGMPv3 capable.
*/
case TYPE_IGMPV1_MEMBERSHIP_REPORT:
case TYPE_IGMPV2_MEMBERSHIP_REPORT:
case TYPE_IGMPV2_LEAVE_GROUP:
igmp.unsupportTypeData = bb.array(); // Is this the entire array?
msg = "IGMP message type: " + igmp.igmpType + " is not supported";
igmp.log.debug(msg);
break;
default:
msg = "IGMP message type: " + igmp.igmpType + " is not recognized";
igmp.unsupportTypeData = bb.array();
igmp.log.debug(msg);
break;
}
return igmp;
};
}