src/java/iotcloud/Table.java

   1 package iotcloud;
   2 import java.util.HashMap;
   3 import java.util.Arrays;
   4 import java.util.Vector;
   5 import javax.crypto.spec.*;
   6 import javax.crypto.*;
   7
   8 final public class Table {
   9         private int numslots;
  10         private HashMap<IoTString, KeyValue> table=new HashMap<IoTString, KeyValue>();
  11         private HashMap<Long, Pair<Long, Liveness> > lastmessagetable=new HashMap<Long, Pair<Long, Liveness> >();
  12         private SlotBuffer buffer;
  13         private CloudComm cloud;
  14         private Mac hmac;
  15         private long sequencenumber;
  16         private long localmachineid;
  17   private TableStatus lastTableStatus;
  18   static final int FREE_SLOTS = 10;
  19   static final int FORCED_RESIZE_INCREMENT = 20;
  20
  21         public Table(String baseurl, String password, long _localmachineid) {
  22                 localmachineid=_localmachineid;
  23                 buffer = new SlotBuffer();
  24                 numslots = buffer.capacity();
  25                 sequencenumber = 0;
  26                 initCloud(baseurl, password);
  27         }
  28
  29         public Table(CloudComm _cloud, long _localmachineid) {
  30                 localmachineid=_localmachineid;
  31                 buffer = new SlotBuffer();
  32                 numslots = buffer.capacity();
  33                 sequencenumber = 0;
  34                 cloud=_cloud;
  35         }
  36
  37         private void initCloud(String baseurl, String password) {
  38                 try {
  39                         SecretKeySpec secret=getKey(password);
  40                         Cipher encryptCipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
  41                         encryptCipher.init(Cipher.ENCRYPT_MODE, secret);
  42                         Cipher decryptCipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
  43                         decryptCipher.init(Cipher.DECRYPT_MODE, secret);
  44                         hmac = Mac.getInstance("HmacSHA256");
  45                         hmac.init(secret);
  46                         cloud=new CloudComm(baseurl, encryptCipher, decryptCipher, hmac);
  47                 } catch (Exception e) {
  48                         throw new Error("Failed To Initialize Ciphers");
  49                 }
  50         }
  51
  52         private SecretKeySpec getKey(String password) {
  53                 try {
  54                         PBEKeySpec keyspec = new PBEKeySpec(password.toCharArray());
  55                         SecretKey key = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA256").generateSecret(keyspec);
  56                         SecretKeySpec secret = new SecretKeySpec(key.getEncoded(), "AES");
  57                         return secret;
  58                 } catch (Exception e) {
  59                         throw new Error("Failed generating key.");
  60                 }
  61         }
  62
  63         public void update() {
  64                 Slot[] newslots=cloud.getSlots(sequencenumber+1);
  65                 validateandupdate(newslots, false);
  66         }
  67
  68         public IoTString get(IoTString key) {
  69                 KeyValue kv=table.get(key);
  70                 if (kv != null)
  71                         return kv.getValue();
  72                 else
  73                         return null;
  74         }
  75
  76         public void initTable() {
  77                 Slot s=new Slot(1, localmachineid);
  78                 TableStatus status=new TableStatus(s, numslots);
  79                 s.addEntry(status);
  80     Slot[] array=cloud.putSlot(s, numslots);
  81     if (array == null) {
  82       array = new Slot[] {s};
  83                         validateandupdate(array, true); // update data structure
  84                 } else {
  85                         throw new Error("Error on initialization");
  86                 }
  87         }
  88
  89         public IoTString put(IoTString key, IoTString value) {
  90     while(true) {
  91       KeyValue oldvalue=table.get(key);
  92       if (tryput(key, value, false)) {
  93                                 if (oldvalue==null)
  94                                         return null;
  95                                 else
  96                                         return oldvalue.getValue();
  97       }
  98     }
  99   }
 100
 101   private boolean tryput(IoTString key, IoTString value, boolean forcedresize) {
 102                 Slot s=new Slot(sequencenumber+1, localmachineid, buffer.getSlot(sequencenumber).getHMAC());
 103     long seqn = buffer.getOldestSeqNum();
 104
 105                 if (forcedresize) {
 106                         TableStatus status=new TableStatus(s, FORCED_RESIZE_INCREMENT + numslots);
 107                         s.addEntry(status);
 108                 }
 109
 110     if ((numslots - buffer.size()) < FREE_SLOTS) {
 111       //have to check whether we have enough free slots
 112       seqn = buffer.getNewestSeqNum() + 1 - numslots;
 113       for(int i=0; i < FREE_SLOTS; i++, seqn++) {
 114         Slot prevslot=buffer.getSlot(seqn);
 115         if (!prevslot.isLive())
 116           continue;
 117         Vector<Entry> liveentries = prevslot.getLiveEntries();
 118         for(Entry liveentry:liveentries) {
 119                                         if (redundant(liveentry))
 120                                                 continue;
 121           if (s.hasSpace(liveentry))
 122             s.addEntry(liveentry);
 123           else if (i==0) {
 124             if (s.canFit(liveentry))
 125               s.addEntry(liveentry);
 126             else if (!forcedresize) {
 127               return tryput(key, value, true);
 128                                                 }
 129                                         }
 130         }
 131       }
 132     }
 133     KeyValue kv=new KeyValue(s, key, value);
 134     boolean insertedkv=false;
 135     if (s.hasSpace(kv)) {
 136       s.addEntry(kv);
 137       insertedkv=true;
 138     }
 139
 140     long newestseqnum=buffer.getNewestSeqNum();
 141     search:
 142     for(;seqn<=newestseqnum;seqn++) {
 143       Slot prevslot=buffer.getSlot(seqn);
 144       if (!prevslot.isLive())
 145         continue;
 146       Vector<Entry> liveentries = prevslot.getLiveEntries();
 147       for(Entry liveentry:liveentries) {
 148                                 if (redundant(liveentry))
 149                                         continue;
 150         if (s.hasSpace(liveentry))
 151           s.addEntry(liveentry);
 152         else
 153           break search;
 154       }
 155     }
 156
 157     int max=0;
 158     if (forcedresize)
 159       max = numslots + FORCED_RESIZE_INCREMENT;
 160     Slot[] array=cloud.putSlot(s, max);
 161     if (array == null)
 162       array = new Slot[] {s};
 163     else
 164       insertedkv=false;
 165
 166                 validateandupdate(array, true); // update data structure
 167
 168     return insertedkv;
 169         }
 170
 171         boolean redundant(Entry liveentry) {
 172                 if (liveentry.getType()==Entry.TypeLastMessage) {
 173                         LastMessage lastmsg=(LastMessage) liveentry;
 174                         return lastmsg.getMachineID() == localmachineid;
 175                 }
 176                 return false;
 177         }
 178
 179
 180         private void validateandupdate(Slot[] newslots, boolean isput) {
 181                 //The cloud communication layer has checked slot HMACs already
 182                 //before decoding
 183                 if (newslots.length==0)
 184                         return;
 185
 186                 long firstseqnum=newslots[0].getSequenceNumber();
 187                 if (firstseqnum <= sequencenumber)
 188                         throw new Error("Server Error: Sent older slots!");
 189
 190                 SlotIndexer indexer = new SlotIndexer(newslots, buffer);
 191                 checkHMACChain(indexer, newslots);
 192
 193     initExpectedSize();
 194     for(Slot slot: newslots) {
 195       updateExpectedSize();
 196                         processSlot(indexer, slot, isput);
 197                 }
 198
 199                 //If there is a gap, check to see if the server sent us everything
 200                 if (firstseqnum != (sequencenumber+1))
 201                         checkNumSlots(newslots.length);
 202
 203     commitNewMaxSize();
 204
 205     //commit new to slots
 206     for(Slot slot:newslots) {
 207       buffer.putSlot(slot);
 208     }
 209                 sequencenumber = newslots[newslots.length - 1].getSequenceNumber();
 210         }
 211
 212   private int expectedsize, currmaxsize;
 213
 214   private void checkNumSlots(int numslots) {
 215     if (numslots != expectedsize)
 216       throw new Error("Server Error: Server did not send all slots.  Expected: "+expectedsize+" Received:"+numslots);
 217   }
 218
 219   private void initExpectedSize() {
 220                 long prevslots = sequencenumber;
 221     expectedsize = (prevslots < ((long) numslots)) ? (int) prevslots : numslots;
 222     currmaxsize = numslots;
 223   }
 224
 225   private void updateExpectedSize() {
 226     expectedsize++;
 227     if (expectedsize > currmaxsize)
 228       expectedsize = currmaxsize;
 229   }
 230
 231   private void updateCurrMaxSize(int newmaxsize) {
 232     currmaxsize=newmaxsize;
 233   }
 234
 235   private void commitNewMaxSize() {
 236     if (numslots != currmaxsize)
 237       buffer.resize(currmaxsize);
 238
 239     numslots=currmaxsize;
 240   }
 241
 242         private void processEntry(KeyValue entry, SlotIndexer indexer) {
 243                 IoTString key=entry.getKey();
 244                 KeyValue oldvalue=table.get(key);
 245                 if (oldvalue != null) {
 246                         oldvalue.setDead();
 247                 }
 248                 table.put(key, entry);
 249         }
 250
 251         private void processEntry(LastMessage entry, SlotIndexer indexer) {
 252                 updateLastMessage(entry.getMachineID(), entry.getSequenceNumber(), entry, false);
 253         }
 254
 255         private void processEntry(RejectedMessage entry, SlotIndexer indexer) {
 256                 long oldseqnum=entry.getOldSeqNum();
 257                 long newseqnum=entry.getNewSeqNum();
 258                 boolean isequal=entry.getEqual();
 259                 long machineid=entry.getMachineID();
 260                 for(long seqnum=oldseqnum; seqnum<=newseqnum; seqnum++) {
 261                         Slot slot=indexer.getSlot(seqnum);
 262                         if (slot != null) {
 263                                 long slotmachineid=slot.getMachineID();
 264                                 if (isequal!=(slotmachineid==machineid)) {
 265                                         throw new Error("Server Error: Trying to insert rejected message for slot "+seqnum);
 266                                 }
 267                         }
 268                 }
 269         }
 270
 271         private void processEntry(TableStatus entry, SlotIndexer indexer) {
 272     int newnumslots=entry.getMaxSlots();
 273     updateCurrMaxSize(newnumslots);
 274     if (lastTableStatus != null)
 275       lastTableStatus.setDead();
 276     lastTableStatus = entry;
 277         }
 278
 279         private void updateLastMessage(long machineid, long seqnum, Liveness liveness, boolean isput) {
 280                 Pair<Long, Liveness> lastmsgentry = lastmessagetable.put(machineid, new Pair<Long, Liveness>(seqnum, liveness));
 281                 if (lastmsgentry == null)
 282                         return;
 283
 284                 long lastmsgseqnum = lastmsgentry.getFirst();
 285                 Liveness lastentry = lastmsgentry.getSecond();
 286                 if (lastentry instanceof LastMessage) {
 287                         ((LastMessage)lastentry).setDead();
 288                 } else if (lastentry instanceof Slot) {
 289                         ((Slot)lastentry).setDead();
 290                 } else {
 291                         throw new Error("Unrecognized type");
 292                 }
 293
 294                 if (machineid == localmachineid) {
 295                         if (lastmsgseqnum != seqnum && !isput)
 296                                 throw new Error("Server Error: Mismatch on local machine sequence number");
 297                 } else {
 298                         if (lastmsgseqnum > seqnum)
 299                                 throw new Error("Server Error: Rollback on remote machine sequence number");
 300                 }
 301         }
 302
 303         private void processSlot(SlotIndexer indexer, Slot slot, boolean isput) {
 304                 updateLastMessage(slot.getMachineID(), slot.getSequenceNumber(), slot, isput);
 305
 306                 for(Entry entry : slot.getEntries()) {
 307                         switch(entry.getType()) {
 308                         case Entry.TypeKeyValue:
 309                                 processEntry((KeyValue)entry, indexer);
 310                                 break;
 311
 312                         case Entry.TypeLastMessage:
 313                                 processEntry((LastMessage)entry, indexer);
 314                                 break;
 315
 316                         case Entry.TypeRejectedMessage:
 317                                 processEntry((RejectedMessage)entry, indexer);
 318                                 break;
 319
 320                         case Entry.TypeTableStatus:
 321                                 processEntry((TableStatus)entry, indexer);
 322                                 break;
 323
 324                         default:
 325                                 throw new Error("Unrecognized type: "+entry.getType());
 326                         }
 327                 }
 328         }
 329
 330         private void checkHMACChain(SlotIndexer indexer, Slot[] newslots) {
 331                 for(int i=0; i < newslots.length; i++) {
 332                         Slot currslot=newslots[i];
 333                         Slot prevslot=indexer.getSlot(currslot.getSequenceNumber()-1);
 334                         if (prevslot != null &&
 335                                         !Arrays.equals(prevslot.getHMAC(), currslot.getPrevHMAC()))
 336                                 throw new Error("Server Error: Invalid HMAC Chain");
 337                 }
 338         }
 339 }