Robust/src/Runtime/DSTM/interface/trans.c

   1 #include "dstm.h"
   2 #include "ip.h"
   3 #include "clookup.h"
   4 #include "machinepile.h"
   5 #include "mlookup.h"
   6 #include "llookup.h"
   7 #include "plookup.h"
   8 #include "prelookup.h"
   9 #include "queue.h"
  10 #include <pthread.h>
  11 #include <sys/types.h>
  12 #include <sys/socket.h>
  13 #include <netdb.h>
  14 #include <netinet/in.h>
  15 #include <sys/types.h>
  16 #include <unistd.h>
  17 #include <errno.h>
  18 #include <time.h>
  19 #include <string.h>
  20 #include <pthread.h>
  21
  22 #define LISTEN_PORT 2156
  23 #define RECEIVE_BUFFER_SIZE 2048
  24 #define NUM_THREADS 10
  25 #define PREFETCH_CACHE_SIZE 1048576 //1MB
  26 #define CONFIG_FILENAME "dstm.conf"
  27
  28 /* Global Variables */
  29 extern int classsize[];
  30 extern primarypfq_t pqueue; // shared prefetch queue
  31 extern mcpileq_t mcqueue;  //Shared queue containing prefetch requests sorted by remote machineids
  32 objstr_t *prefetchcache; //Global Prefetch cache
  33 pthread_mutex_t prefetchcache_mutex;// Mutex to lock Prefetch Cache
  34 extern pthread_mutex_t mainobjstore_mutex;// Mutex to lock main Object store
  35 extern prehashtable_t pflookup; //Global Prefetch cache's lookup table
  36 pthread_t wthreads[NUM_THREADS]; //Worker threads for working on the prefetch queue
  37 pthread_t tPrefetch;            /* Primary Prefetch thread that processes the prefetch queue */
  38 extern objstr_t *mainobjstore;
  39 unsigned int myIpAddr;
  40 unsigned int *hostIpAddrs;
  41 int sizeOfHostArray;
  42 int numHostsInSystem;
  43 int myIndexInHostArray;
  44 unsigned int oidsPerBlock;
  45 unsigned int oidMin;
  46 unsigned int oidMax;
  47
  48 plistnode_t *createPiles(transrecord_t *);
  49 inline int arrayLength(int *array) {
  50         int i;
  51         for(i=0 ;array[i] != -1; i++)
  52                 ;
  53         return i;
  54 }
  55 inline int findmax(int *array, int arraylength) {
  56         int max, i;
  57         max = array[0];
  58         for(i = 0; i < arraylength; i++){
  59                 if(array[i] > max) {
  60                         max = array[i];
  61                 }
  62         }
  63         return max;
  64 }
  65 /* This function is a prefetch call generated by the compiler that
  66  * populates the shared primary prefetch queue*/
  67 void prefetch(int ntuples, unsigned int *oids, unsigned short *endoffsets, short *arrayfields) {
  68         int qnodesize;
  69         int len = 0;
  70
  71         /* Allocate for the queue node*/
  72         char *node;
  73         qnodesize = sizeof(prefetchqelem_t) + sizeof(int) + ntuples * (sizeof(short) + sizeof(unsigned int)) + endoffsets[ntuples - 1] * sizeof(short);
  74         if((node = calloc(1, qnodesize)) == NULL) {
  75                 printf("Calloc Error %s, %d\n", __FILE__, __LINE__);
  76                 return;
  77         }
  78         /* Set queue node values */
  79         len = sizeof(prefetchqelem_t);
  80         memcpy(node + len, &ntuples, sizeof(int));
  81         len += sizeof(int);
  82         memcpy(node + len, oids, ntuples*sizeof(unsigned int));
  83         len += ntuples * sizeof(unsigned int);
  84         memcpy(node + len, endoffsets, ntuples*sizeof(short));
  85         len += ntuples * sizeof(short);
  86         memcpy(node + len, arrayfields, endoffsets[ntuples-1]*sizeof(short));
  87         /* Lock and insert into primary prefetch queue */
  88         pthread_mutex_lock(&pqueue.qlock);
  89         pre_enqueue((prefetchqelem_t *)node);
  90         pthread_cond_signal(&pqueue.qcond);
  91         pthread_mutex_unlock(&pqueue.qlock);
  92 }
  93
  94 /* This function starts up the transaction runtime. */
  95 int dstmStartup(const char * option) {
  96   pthread_t thread_Listen;
  97   pthread_attr_t attr;
  98   int master=option!=NULL && strcmp(option, "master")==0;
  99
 100         if (processConfigFile() != 0)
 101                 return 0; //TODO: return error value, cause main program to exit
 102
 103   dstmInit();
 104   transInit();
 105
 106   if (master) {
 107     pthread_attr_init(&attr);
 108     pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE);
 109     pthread_create(&thread_Listen, &attr, dstmListen, NULL);
 110     return 1;
 111   } else {
 112     dstmListen();
 113     return 0;
 114   }
 115
 116 }
 117
 118
 119 /* This function initiates the prefetch thread
 120  * A queue is shared between the main thread of execution
 121  * and the prefetch thread to process the prefetch call
 122  * Call from compiler populates the shared queue with prefetch requests while prefetch thread
 123  * processes the prefetch requests */
 124 void transInit() {
 125         int t, rc;
 126         //Create and initialize prefetch cache structure
 127         prefetchcache = objstrCreate(PREFETCH_CACHE_SIZE);
 128         pthread_mutex_init(&prefetchcache_mutex, NULL);
 129         //Create prefetch cache lookup table
 130         if(prehashCreate(HASH_SIZE, LOADFACTOR))
 131                 return; //Failure
 132         //Initialize primary shared queue
 133         queueInit();
 134         //Initialize machine pile w/prefetch oids and offsets shared queue
 135         mcpileqInit();
 136         //Create the primary prefetch thread
 137         pthread_create(&tPrefetch, NULL, transPrefetch, NULL);
 138         //Create and Initialize a pool of threads
 139         /* Threads are active for the entire period runtime is running */
 140         for(t = 0; t< NUM_THREADS; t++) {
 141                 rc = pthread_create(&wthreads[t], NULL, mcqProcess, (void *)t);
 142                 if (rc) {
 143                         printf("Thread create error %s, %d\n", __FILE__, __LINE__);
 144                         return;
 145                 }
 146         }
 147 }
 148
 149 /* This function stops the threads spawned */
 150 void transExit() {
 151         int t;
 152         pthread_cancel(tPrefetch);
 153         for(t = 0; t < NUM_THREADS; t++)
 154                 pthread_cancel(wthreads[t]);
 155
 156         return;
 157 }
 158
 159 /* This functions inserts randowm wait delays in the order of msec
 160  * Mostly used when transaction commits retry*/
 161 void randomdelay(void)
 162 {
 163         struct timespec req, rem;
 164         time_t t;
 165
 166         t = time(NULL);
 167         req.tv_sec = 0;
 168         req.tv_nsec = (long)(1000000 + (t%10000000)); //1-11 msec
 169         nanosleep(&req, &rem);
 170         return;
 171 }
 172
 173 /* This function initializes things required in the transaction start*/
 174 transrecord_t *transStart()
 175 {
 176         transrecord_t *tmp = malloc(sizeof(transrecord_t));
 177         tmp->cache = objstrCreate(1048576);
 178         tmp->lookupTable = chashCreate(HASH_SIZE, LOADFACTOR);
 179 #ifdef COMPILER
 180         tmp->revertlist=NULL;
 181 #endif
 182         return tmp;
 183 }
 184
 185 /* This function finds the location of the objects involved in a transaction
 186  * and returns the pointer to the object if found in a remote location */
 187 objheader_t *transRead(transrecord_t *record, unsigned int oid) {
 188         unsigned int machinenumber;
 189         objheader_t *tmp, *objheader;
 190         objheader_t *objcopy;
 191         int size, rc, found = 0;
 192         void *buf;
 193         struct timespec ts;
 194         struct timeval tp;
 195
 196         rc = gettimeofday(&tp, NULL);
 197
 198         /* Convert from timeval to timespec */
 199         ts.tv_nsec = tp.tv_usec * 10;
 200
 201         /* Search local transaction cache */
 202         if((objheader = (objheader_t *)chashSearch(record->lookupTable, oid)) != NULL){
 203 #ifdef COMPILER
 204           return &objheader[1];
 205 #else
 206           return objheader;
 207 #endif
 208         } else if ((objheader = (objheader_t *) mhashSearch(oid)) != NULL) {
 209                 /* Look up in machine lookup table  and copy  into cache*/
 210                 tmp = mhashSearch(oid);
 211                 GETSIZE(size, tmp);
 212                 size += sizeof(objheader_t);
 213                 //TODO:Lock the local trans cache while copying the object here
 214                 objcopy = objstrAlloc(record->cache, size);
 215                 memcpy(objcopy, (void *)objheader, size);
 216                 /* Insert into cache's lookup table */
 217                 chashInsert(record->lookupTable, OID(objheader), objcopy);
 218 #ifdef COMPILER
 219                 return &objcopy[1];
 220 #else
 221                 return objcopy;
 222 #endif
 223         } else if((tmp = (objheader_t *) prehashSearch(oid)) != NULL) { /* Look up in prefetch cache */
 224                 found = 1;
 225                 GETSIZE(size, tmp);
 226                 size+=sizeof(objheader_t);
 227                 //TODO:Lock the local  trans cache while copying the object here
 228                 objcopy = objstrAlloc(record->cache, size);
 229                 memcpy(objcopy, (void *)tmp, size);
 230                 /* Insert into cache's lookup table */
 231                 chashInsert(record->lookupTable, OID(tmp), objcopy);
 232 #ifdef COMPILER
 233                 return &objcopy[1];
 234 #else
 235                 return objcopy;
 236 #endif
 237         } else {
 238                 /*If object not found in prefetch cache then block until object appears in the prefetch cache */
 239                 pthread_mutex_lock(&prefetchcache_mutex);
 240                 while(!found) {
 241                         rc = pthread_cond_timedwait(&pflookup.cond, &pflookup.lock, &ts);
 242                         if(rc == ETIMEDOUT) {
 243                                 printf("Wait timed out\n");
 244                                 /* Check Prefetch cache again */
 245                                 if((tmp =(objheader_t *) prehashSearch(oid)) != NULL) {
 246                                         found = 1;
 247                                         GETSIZE(size,tmp);
 248                                         size+=sizeof(objheader_t);
 249                                         objcopy = objstrAlloc(record->cache, size);
 250                                         memcpy(objcopy, (void *)tmp, size);
 251                                         chashInsert(record->lookupTable, OID(tmp), objcopy);
 252                                         pthread_mutex_unlock(&prefetchcache_mutex);
 253 #ifdef COMPILER
 254                                         return &objcopy[1];
 255 #else
 256                                         return objcopy;
 257 #endif
 258                                 } else {
 259                                         pthread_mutex_unlock(&prefetchcache_mutex);
 260                                         break;
 261                                 }
 262                         }
 263                 }
 264
 265                 /* Get the object from the remote location */
 266                 machinenumber = lhashSearch(oid);
 267                 objcopy = getRemoteObj(record, machinenumber, oid);
 268                 if(objcopy == NULL) {
 269                         printf("Object not found in Remote location %s, %d\n", __FILE__, __LINE__);
 270                         return NULL;
 271                 } else {
 272 #ifdef COMPILER
 273                   return &objcopy[1];
 274 #else
 275                   return objcopy;
 276 #endif
 277                 }
 278         }
 279 }
 280
 281 /* This function creates objects in the transaction record */
 282 objheader_t *transCreateObj(transrecord_t *record, unsigned int size)
 283 {
 284   objheader_t *tmp = (objheader_t *) objstrAlloc(record->cache, (sizeof(objheader_t) + size));
 285   OID(tmp) = getNewOID();
 286   tmp->version = 1;
 287   tmp->rcount = 1;
 288   STATUS(tmp) = NEW;
 289   chashInsert(record->lookupTable, OID(tmp), tmp);
 290 #ifdef COMPILER
 291   return &tmp[1]; //want space after object header
 292 #else
 293   return tmp;
 294 #endif
 295 }
 296
 297 /* This function creates machine piles based on all machines involved in a
 298  * transaction commit request */
 299 plistnode_t *createPiles(transrecord_t *record) {
 300         int i = 0;
 301         unsigned int size;/* Represents number of bins in the chash table */
 302         chashlistnode_t *curr, *ptr, *next;
 303         plistnode_t *pile = NULL;
 304         unsigned int machinenum;
 305         void *localmachinenum;
 306         objheader_t *headeraddr;
 307
 308         ptr = record->lookupTable->table;
 309         size = record->lookupTable->size;
 310
 311         for(i = 0; i < size ; i++) {
 312                 curr = &ptr[i];
 313                 /* Inner loop to traverse the linked list of the cache lookupTable */
 314                 while(curr != NULL) {
 315                         //if the first bin in hash table is empty
 316                         if(curr->key == 0) {
 317                                 break;
 318                         }
 319                         next = curr->next;
 320
 321                         if ((headeraddr = chashSearch(record->lookupTable, curr->key)) == NULL) {
 322                                 printf("Error: No such oid %s, %d\n", __FILE__, __LINE__);
 323                                 return NULL;
 324                         }
 325
 326                         //Get machine location for object id (and whether local or not)
 327                         if (STATUS(headeraddr) & NEW || mhashSearch(curr->key) != NULL) {
 328                                 machinenum = myIpAddr;
 329                         } else  if ((machinenum = lhashSearch(curr->key)) == 0) {
 330                                 printf("Error: No such machine %s, %d\n", __FILE__, __LINE__);
 331                                 return NULL;
 332                         }
 333
 334                         //Make machine groups
 335                         if ((pile = pInsert(pile, headeraddr, machinenum, record->lookupTable->numelements)) == NULL) {
 336                                 printf("pInsert error %s, %d\n", __FILE__, __LINE__);
 337                                 return NULL;
 338                         }
 339
 340                         curr = next;
 341                 }
 342         }
 343         return pile;
 344 }
 345
 346 /* This function initiates the transaction commit process
 347  * Spawns threads for each of the new connections with Participants
 348  * and creates new piles by calling the createPiles(),
 349  * Sends a transrequest() to each remote machines for objects found remotely
 350  * and calls handleLocalReq() to process objects found locally */
 351 int transCommit(transrecord_t *record) {
 352         unsigned int tot_bytes_mod, *listmid;
 353         plistnode_t *pile, *pile_ptr;
 354         int i, j, rc, val;
 355         int pilecount, offset, threadnum, trecvcount;
 356         char buffer[RECEIVE_BUFFER_SIZE],control;
 357         char transid[TID_LEN];
 358         trans_req_data_t *tosend;
 359         trans_commit_data_t transinfo;
 360         static int newtid = 0;
 361         char treplyctrl = 0, treplyretry = 0; /* keeps track of the common response that needs to be sent */
 362         char localstat = 0;
 363
 364         do {
 365                 trecvcount = 0;
 366                 threadnum = 0;
 367
 368                 /* Look through all the objects in the transaction record and make piles
 369                  * for each machine involved in the transaction*/
 370                 pile_ptr = pile = createPiles(record);
 371
 372                 /* Create the packet to be sent in TRANS_REQUEST */
 373
 374                 /* Count the number of participants */
 375                 pilecount = pCount(pile);
 376
 377                 /* Create a list of machine ids(Participants) involved in transaction   */
 378                 if((listmid = calloc(pilecount, sizeof(unsigned int))) == NULL) {
 379                         printf("Calloc error %s, %d\n", __FILE__, __LINE__);
 380                         free(record);
 381                         return 1;
 382                 }
 383                 pListMid(pile, listmid);
 384
 385
 386                 /* Initialize thread variables,
 387                  * Spawn a thread for each Participant involved in a transaction */
 388                 pthread_t thread[pilecount];
 389                 pthread_attr_t attr;
 390                 pthread_cond_t tcond;
 391                 pthread_mutex_t tlock;
 392                 pthread_mutex_t tlshrd;
 393
 394                 thread_data_array_t *thread_data_array;
 395                 if((thread_data_array = (thread_data_array_t *) malloc(sizeof(thread_data_array_t)*pilecount)) == NULL) {
 396                         printf("Malloc error %s, %d\n", __FILE__, __LINE__);
 397                         pthread_cond_destroy(&tcond);
 398                         pthread_mutex_destroy(&tlock);
 399                         pDelete(pile_ptr);
 400                         free(listmid);
 401                         free(record);
 402                         return 1;
 403                 }
 404
 405                 local_thread_data_array_t *ltdata;
 406                 if((ltdata = calloc(1, sizeof(local_thread_data_array_t))) == NULL) {
 407                         printf("Calloc error %s, %d\n", __FILE__, __LINE__);
 408                         pthread_cond_destroy(&tcond);
 409                         pthread_mutex_destroy(&tlock);
 410                         pDelete(pile_ptr);
 411                         free(listmid);
 412                         free(thread_data_array);
 413                         free(record);
 414                         return 1;
 415                 }
 416
 417                 thread_response_t rcvd_control_msg[pilecount];  /* Shared thread array that keeps track of responses of participants */
 418
 419                 /* Initialize and set thread detach attribute */
 420                 pthread_attr_init(&attr);
 421                 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE);
 422                 pthread_mutex_init(&tlock, NULL);
 423                 pthread_cond_init(&tcond, NULL);
 424
 425                 /* Process each machine pile */
 426                 while(pile != NULL) {
 427                         //Create transaction id
 428                         newtid++;
 429                         if ((tosend = calloc(1, sizeof(trans_req_data_t))) == NULL) {
 430                                 printf("Calloc error %s, %d\n", __FILE__, __LINE__);
 431                                 pthread_cond_destroy(&tcond);
 432                                 pthread_mutex_destroy(&tlock);
 433                                 pDelete(pile_ptr);
 434                                 free(listmid);
 435                                 free(thread_data_array);
 436                                 free(ltdata);
 437                                 free(record);
 438                                 return 1;
 439                         }
 440                         tosend->f.control = TRANS_REQUEST;
 441                         sprintf(tosend->f.trans_id, "%x_%d", pile->mid, newtid);
 442                         tosend->f.mcount = pilecount;
 443                         tosend->f.numread = pile->numread;
 444                         tosend->f.nummod = pile->nummod;
 445                         tosend->f.numcreated = pile->numcreated;
 446                         tosend->f.sum_bytes = pile->sum_bytes;
 447                         tosend->listmid = listmid;
 448                         tosend->objread = pile->objread;
 449                         tosend->oidmod = pile->oidmod;
 450                         tosend->oidcreated = pile->oidcreated;
 451                         thread_data_array[threadnum].thread_id = threadnum;
 452                         thread_data_array[threadnum].mid = pile->mid;
 453                         thread_data_array[threadnum].buffer = tosend;
 454                         thread_data_array[threadnum].recvmsg = rcvd_control_msg;
 455                         thread_data_array[threadnum].threshold = &tcond;
 456                         thread_data_array[threadnum].lock = &tlock;
 457                         thread_data_array[threadnum].count = &trecvcount;
 458                         thread_data_array[threadnum].replyctrl = &treplyctrl;
 459                         thread_data_array[threadnum].replyretry = &treplyretry;
 460                         thread_data_array[threadnum].rec = record;
 461                         /* If local do not create any extra connection */
 462                         if(pile->mid != myIpAddr) { /* Not local */
 463                                 rc = pthread_create(&thread[threadnum], &attr, transRequest, (void *) &thread_data_array[threadnum]);
 464                                 if(rc) {
 465                                         perror("Error in pthread create\n");
 466                                         pthread_cond_destroy(&tcond);
 467                                         pthread_mutex_destroy(&tlock);
 468                                         pDelete(pile_ptr);
 469                                         free(listmid);
 470                                         for (i = 0; i < threadnum; i++)
 471                                                 free(thread_data_array[i].buffer);
 472                                         free(thread_data_array);
 473                                         free(ltdata);
 474                                         free(record);
 475                                         return 1;
 476                                 }
 477                         } else { /*Local*/
 478                                 ltdata->tdata = &thread_data_array[threadnum];
 479                                 ltdata->transinfo = &transinfo;
 480                                 val = pthread_create(&thread[threadnum], &attr, handleLocalReq, (void *) ltdata);
 481                                 if(val) {
 482                                         perror("Error in pthread create\n");
 483                                         pthread_cond_destroy(&tcond);
 484                                         pthread_mutex_destroy(&tlock);
 485                                         pDelete(pile_ptr);
 486                                         free(listmid);
 487                                         for (i = 0; i < threadnum; i++)
 488                                                 free(thread_data_array[i].buffer);
 489                                         free(thread_data_array);
 490                                         free(ltdata);
 491                                         free(record);
 492                                         return 1;
 493                                 }
 494                         }
 495
 496                         threadnum++;
 497                         pile = pile->next;
 498                 }
 499
 500                 /* Free attribute and wait for the other threads */
 501                 pthread_attr_destroy(&attr);
 502
 503                 for (i = 0; i < pilecount; i++) {
 504                         rc = pthread_join(thread[i], NULL);
 505                         if(rc)
 506                         {
 507                                 printf("ERROR return code from pthread_join() is %d\n", rc);
 508                                 pthread_cond_destroy(&tcond);
 509                                 pthread_mutex_destroy(&tlock);
 510                                 pDelete(pile_ptr);
 511                                 free(listmid);
 512                                 for (j = i; j < pilecount; j++)
 513                                         free(thread_data_array[j].buffer);
 514                                 free(thread_data_array);
 515                                 free(ltdata);
 516                                 free(record);
 517                                 return 1;
 518                         }
 519                         free(thread_data_array[i].buffer);
 520                 }
 521
 522
 523                 /* Free resources */
 524                 pthread_cond_destroy(&tcond);
 525                 pthread_mutex_destroy(&tlock);
 526                 free(listmid);
 527                 pDelete(pile_ptr);
 528                 free(thread_data_array);
 529                 free(ltdata);
 530
 531                 /* wait a random amount of time */
 532                 if (treplyretry == 1)
 533                         randomdelay();
 534
 535         /* Retry trans commit procedure if not sucessful in the first try */
 536         } while (treplyretry == 1);
 537
 538         free(record);
 539         return 0;
 540 }
 541
 542 /* This function sends information involved in the transaction request
 543  * to participants and accepts a response from particpants.
 544  * It calls decideresponse() to decide on what control message
 545  * to send next to participants and sends the message using sendResponse()*/
 546 void *transRequest(void *threadarg) {
 547         int sd, i, n;
 548         struct sockaddr_in serv_addr;
 549         struct hostent *server;
 550         thread_data_array_t *tdata;
 551         objheader_t *headeraddr;
 552         char buffer[RECEIVE_BUFFER_SIZE], control, recvcontrol;
 553         char machineip[16], retval;
 554
 555         tdata = (thread_data_array_t *) threadarg;
 556
 557         /* Send Trans Request */
 558         if ((sd = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
 559                 perror("Error in socket for TRANS_REQUEST\n");
 560                 pthread_exit(NULL);
 561         }
 562         bzero((char*) &serv_addr, sizeof(serv_addr));
 563         serv_addr.sin_family = AF_INET;
 564         serv_addr.sin_port = htons(LISTEN_PORT);
 565         midtoIP(tdata->mid,machineip);
 566         machineip[15] = '\0';
 567         serv_addr.sin_addr.s_addr = inet_addr(machineip);
 568         /* Open Connection */
 569         if (connect(sd, (struct sockaddr *) &serv_addr, sizeof(struct sockaddr)) < 0) {
 570                 perror("Error in connect for TRANS_REQUEST\n");
 571                 close(sd);
 572                 pthread_exit(NULL);
 573         }
 574
 575         printf("DEBUG-> trans.c Sending TRANS_REQUEST to mid %s\n", machineip);
 576         /* Send bytes of data with TRANS_REQUEST control message */
 577         if (send(sd, &(tdata->buffer->f), sizeof(fixed_data_t),MSG_NOSIGNAL) < sizeof(fixed_data_t)) {
 578                 perror("Error sending fixed bytes for thread\n");
 579                 close(sd);
 580                 pthread_exit(NULL);
 581         }
 582         /* Send list of machines involved in the transaction */
 583         {
 584                 int size=sizeof(unsigned int)*tdata->buffer->f.mcount;
 585                 if (send(sd, tdata->buffer->listmid, size, MSG_NOSIGNAL) < size) {
 586                         perror("Error sending list of machines for thread\n");
 587                         close(sd);
 588                         pthread_exit(NULL);
 589                 }
 590         }
 591         /* Send oids and version number tuples for objects that are read */
 592         {
 593                 int size=(sizeof(unsigned int)+sizeof(short))*tdata->buffer->f.numread;
 594                 if (send(sd, tdata->buffer->objread, size, MSG_NOSIGNAL) < size) {
 595                         perror("Error sending tuples for thread\n");
 596                         close(sd);
 597                         pthread_exit(NULL);
 598                 }
 599         }
 600         /* Send objects that are modified */
 601         for(i = 0; i < tdata->buffer->f.nummod ; i++) {
 602                 int size;
 603                 headeraddr = chashSearch(tdata->rec->lookupTable, tdata->buffer->oidmod[i]);
 604                 GETSIZE(size,headeraddr);
 605                 size+=sizeof(objheader_t);
 606                 if (send(sd, headeraddr, size, MSG_NOSIGNAL)  < size) {
 607                         perror("Error sending obj modified for thread\n");
 608                         close(sd);
 609                         pthread_exit(NULL);
 610                 }
 611         }
 612
 613         /* Read control message from Participant */
 614         if((n = read(sd, &control, sizeof(char))) <= 0) {
 615                 perror("Error in reading control message from Participant\n");
 616                 close(sd);
 617                 pthread_exit(NULL);
 618         }
 619         recvcontrol = control;
 620
 621         /* Update common data structure and increment count */
 622         tdata->recvmsg[tdata->thread_id].rcv_status = recvcontrol;
 623
 624         /* Lock and update count */
 625         /* Thread sleeps until all messages from pariticipants are received by coordinator */
 626         pthread_mutex_lock(tdata->lock);
 627
 628         (*(tdata->count))++; /* keeps track of no of messages received by the coordinator */
 629
 630         /* Wake up the threads and invoke decideResponse (once) */
 631         if(*(tdata->count) == tdata->buffer->f.mcount) {
 632                 decideResponse(tdata);
 633                 pthread_cond_broadcast(tdata->threshold);
 634         } else {
 635                 pthread_cond_wait(tdata->threshold, tdata->lock);
 636         }
 637         pthread_mutex_unlock(tdata->lock);
 638
 639         /* Send the final response such as TRANS_COMMIT or TRANS_ABORT t
 640          * to all participants in their respective socket */
 641         if (sendResponse(tdata, sd) == 0) {
 642                 printf("sendResponse returned error %s,%d\n", __FILE__, __LINE__);
 643                 close(sd);
 644                 pthread_exit(NULL);
 645         }
 646
 647         /* Close connection */
 648         close(sd);
 649         pthread_exit(NULL);
 650 }
 651
 652 /* This function decides the reponse that needs to be sent to
 653  * all Participant machines after the TRANS_REQUEST protocol */
 654 void decideResponse(thread_data_array_t *tdata) {
 655         char control;
 656         int i, transagree = 0, transdisagree = 0, transsoftabort = 0; /* Counters to formulate decision of what
 657                                                                          message to send */
 658
 659         for (i = 0 ; i < tdata->buffer->f.mcount; i++) {
 660                 control = tdata->recvmsg[i].rcv_status; /* tdata: keeps track of all participant responses
 661                                                            written onto the shared array */
 662                 switch(control) {
 663                         default:
 664                                 printf("Participant sent unknown message in %s, %d\n", __FILE__, __LINE__);
 665                                 /* treat as disagree, pass thru */
 666                         case TRANS_DISAGREE:
 667                                 transdisagree++;
 668                                 break;
 669
 670                         case TRANS_AGREE:
 671                                 transagree++;
 672                                 break;
 673
 674                         case TRANS_SOFT_ABORT:
 675                                 transsoftabort++;
 676                                 break;
 677                 }
 678         }
 679
 680         /* Send Abort */
 681         if(transdisagree > 0) {
 682                 *(tdata->replyctrl) = TRANS_ABORT;
 683                 /* Free resources */
 684                 objstrDelete(tdata->rec->cache);
 685                 chashDelete(tdata->rec->lookupTable);
 686         } else if(transagree == tdata->buffer->f.mcount){
 687                 /* Send Commit */
 688                 *(tdata->replyctrl) = TRANS_COMMIT;
 689                 /* Free resources */
 690                 objstrDelete(tdata->rec->cache);
 691                 chashDelete(tdata->rec->lookupTable);
 692         } else { /* (transsoftabort > 0 && transdisagree == 0) */
 693                 /* Send Abort in soft abort case followed by retry commiting transaction again*/
 694                 *(tdata->replyctrl) = TRANS_ABORT;
 695                 *(tdata->replyretry) = 1;
 696         }
 697
 698         return;
 699 }
 700 /* This function sends the final response to remote machines per thread in their respective socket id */
 701 char sendResponse(thread_data_array_t *tdata, int sd) {
 702         int n, N, sum, oidcount = 0;
 703         char *ptr, retval = 0;
 704         unsigned int *oidnotfound;
 705
 706         /* If the decided response is due to a soft abort and missing objects at the Participant's side */
 707         if(tdata->recvmsg[tdata->thread_id].rcv_status == TRANS_SOFT_ABORT) {
 708                 /* Read list of objects missing */
 709                 if((read(sd, &oidcount, sizeof(int)) != 0) && (oidcount != 0)) {
 710                         N = oidcount * sizeof(unsigned int);
 711                         if((oidnotfound = calloc(oidcount, sizeof(unsigned int))) == NULL) {
 712                                 printf("Calloc error %s, %d\n", __FILE__, __LINE__);
 713                                 return 0;
 714                         }
 715                         ptr = (char *) oidnotfound;
 716                         do {
 717                                 n = read(sd, ptr+sum, N-sum);
 718                                 sum += n;
 719                         } while(sum < N && n !=0);
 720                 }
 721                 retval =  TRANS_SOFT_ABORT;
 722         }
 723         /* If the decided response is TRANS_ABORT */
 724         if(*(tdata->replyctrl) == TRANS_ABORT) {
 725                 retval = TRANS_ABORT;
 726         } else if(*(tdata->replyctrl) == TRANS_COMMIT) { /* If the decided response is TRANS_COMMIT */
 727                 retval = TRANS_COMMIT;
 728         }
 729
 730         if (send(sd, tdata->replyctrl, sizeof(char),MSG_NOSIGNAL) < sizeof(char)) {
 731                 perror("Error sending ctrl message for participant\n");
 732         }
 733
 734         return retval;
 735 }
 736
 737 /* This function opens a connection, places an object read request to the
 738  * remote machine, reads the control message and object if available  and
 739  * copies the object and its header to the local cache.
 740  * TODO replace mnum and midtoIP() with MACHINE_IP address later */
 741
 742 void *getRemoteObj(transrecord_t *record, unsigned int mnum, unsigned int oid) {
 743         int sd, size, val;
 744         struct sockaddr_in serv_addr;
 745         struct hostent *server;
 746         char control;
 747         char machineip[16];
 748         objheader_t *h;
 749         void *objcopy;
 750
 751         if ((sd = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
 752                 perror("Error in socket\n");
 753                 return NULL;
 754         }
 755         bzero((char*) &serv_addr, sizeof(serv_addr));
 756         serv_addr.sin_family = AF_INET;
 757         serv_addr.sin_port = htons(LISTEN_PORT);
 758         //serv_addr.sin_addr.s_addr = inet_addr(MACHINE_IP);
 759         midtoIP(mnum,machineip);
 760         machineip[15] = '\0';
 761         serv_addr.sin_addr.s_addr = inet_addr(machineip);
 762         /* Open connection */
 763         if (connect(sd, (struct sockaddr *) &serv_addr, sizeof(struct sockaddr)) < 0) {
 764                 perror("Error in connect\n");
 765                 return NULL;
 766         }
 767         char readrequest[sizeof(char)+sizeof(unsigned int)];
 768         readrequest[0] = READ_REQUEST;
 769         *((unsigned int *)(&readrequest[1])) = oid;
 770         if (send(sd, &readrequest, sizeof(readrequest), MSG_NOSIGNAL) < sizeof(readrequest)) {
 771                 perror("Error sending message\n");
 772                 return NULL;
 773         }
 774
 775 #ifdef DEBUG1
 776         printf("DEBUG -> ready to rcv ...\n");
 777 #endif
 778         /* Read response from the Participant */
 779         if((val = read(sd, &control, sizeof(char))) <= 0) {
 780                 perror("No control response for getRemoteObj sent\n");
 781                 return NULL;
 782         }
 783         switch(control) {
 784                 case OBJECT_NOT_FOUND:
 785                         return NULL;
 786                 case OBJECT_FOUND:
 787                         /* Read object if found into local cache */
 788                         if((val = read(sd, &size, sizeof(int))) <= 0) {
 789                                 perror("No size is read from the participant\n");
 790                                 return NULL;
 791                         }
 792                         objcopy = objstrAlloc(record->cache, size);
 793                         if((val = read(sd, objcopy, size)) <= 0) {
 794                                 perror("No objects are read from the remote participant\n");
 795                                 return NULL;
 796                         }
 797                         /* Insert into cache's lookup table */
 798                         chashInsert(record->lookupTable, oid, objcopy);
 799                         break;
 800                 default:
 801                         printf("Error in recv request from participant on a READ_REQUEST %s, %d\n",__FILE__, __LINE__);
 802                         return NULL;
 803         }
 804         /* Close connection */
 805         close(sd);
 806         return objcopy;
 807 }
 808
 809 /* This function handles the local objects involved in a transaction commiting process.
 810  * It also makes a decision if this local machine sends AGREE or DISAGREE or SOFT_ABORT to coordinator.
 811  * Note Coordinator = local machine
 812  * It wakes up the other threads from remote participants that are waiting for the coordinator's decision and
 813  * based on common agreement it either commits or aborts the transaction.
 814  * It also frees the memory resources */
 815 void *handleLocalReq(void *threadarg) {
 816         int val, i = 0, size, offset = 0;
 817         short version;
 818         char control = 0, *ptr;
 819         unsigned int oid;
 820         unsigned int *oidnotfound = NULL, *oidlocked = NULL;
 821         void *mobj, *modptr;
 822         objheader_t *headptr, *headeraddr;
 823         local_thread_data_array_t *localtdata;
 824
 825         localtdata = (local_thread_data_array_t *) threadarg;
 826
 827         /* Counters and arrays to formulate decision on control message to be sent */
 828         oidnotfound = (unsigned int *) calloc((localtdata->tdata->buffer->f.numread + localtdata->tdata->buffer->f.nummod), sizeof(unsigned int));
 829         oidlocked = (unsigned int *) calloc((localtdata->tdata->buffer->f.numread + localtdata->tdata->buffer->f.nummod), sizeof(unsigned int));
 830         int objnotfound = 0, objlocked = 0;
 831         int v_nomatch = 0, v_matchlock = 0, v_matchnolock = 0;
 832
 833         /* modptr points to the beginning of the object store
 834          * created at the Pariticipant */
 835         pthread_mutex_lock(&mainobjstore_mutex);
 836         if ((modptr = objstrAlloc(mainobjstore, localtdata->tdata->buffer->f.sum_bytes)) == NULL) {
 837                 printf("objstrAlloc error for modified objects %s, %d\n", __FILE__, __LINE__);
 838                 pthread_mutex_unlock(&mainobjstore_mutex);
 839                 pthread_exit(NULL);
 840         }
 841         pthread_mutex_unlock(&mainobjstore_mutex);
 842         /* Write modified objects into the mainobject store */
 843         for(i = 0; i< localtdata->tdata->buffer->f.nummod; i++) {
 844                 headeraddr = chashSearch(localtdata->tdata->rec->lookupTable, localtdata->tdata->buffer->oidmod[i]);
 845                 GETSIZE(size,headeraddr);
 846                 size+=sizeof(objheader_t);
 847                 memcpy((char *)modptr+offset, headeraddr, size);
 848                 offset += size;
 849         }
 850         /* Write new objects into the mainobject store */
 851         for(i = 0; i< localtdata->tdata->buffer->f.numcreated; i++) {
 852                 headeraddr = chashSearch(localtdata->tdata->rec->lookupTable, localtdata->tdata->buffer->oidcreated[i]);
 853                 GETSIZE(size, headeraddr);
 854                 size+=sizeof(objheader_t);
 855                 memcpy((char *)modptr+offset, headeraddr, size);
 856                 offset += size;
 857         }
 858
 859         ptr = modptr;
 860         offset = 0; //Reset
 861
 862         /* Process each oid in the machine pile/ group per thread */
 863         for (i = 0; i < localtdata->tdata->buffer->f.numread + localtdata->tdata->buffer->f.nummod; i++) {
 864                 if (i < localtdata->tdata->buffer->f.numread) {//Objs only read and not modified
 865                         int incr = sizeof(unsigned int) + sizeof(short);// Offset that points to next position in the objread array
 866                         incr *= i;
 867                         oid = *((unsigned int *)(localtdata->tdata->buffer->objread + incr));
 868                         incr += sizeof(unsigned int);
 869                         version = *((short *)(localtdata->tdata->buffer->objread + incr));
 870                 } else {//Objs modified
 871                         int tmpsize;
 872                         headptr = (objheader_t *)ptr;
 873                         oid = OID(headptr);
 874                         version = headptr->version;
 875                         GETSIZE(tmpsize, headptr);
 876                         ptr += sizeof(objheader_t) + tmpsize;
 877                 }
 878
 879                 /* Check if object is still present in the machine since the beginning of TRANS_REQUEST */
 880
 881                 /* Save the oids not found and number of oids not found for later use */
 882                 if ((mobj = mhashSearch(oid)) == NULL) {/* Obj not found */
 883                         /* Save the oids not found and number of oids not found for later use */
 884                         oidnotfound[objnotfound] = oid;
 885                         objnotfound++;
 886                 } else { /* If Obj found in machine (i.e. has not moved) */
 887                         /* Check if Obj is locked by any previous transaction */
 888                         if (STATUS(((objheader_t *)mobj)) & LOCK) {
 889                                 if (version == ((objheader_t *)mobj)->version) {      /* If not locked then match versions */
 890                                         v_matchlock++;
 891                                 } else {/* If versions don't match ...HARD ABORT */
 892                                         v_nomatch++;
 893                                         /* Send TRANS_DISAGREE to Coordinator */
 894                                         localtdata->tdata->recvmsg[localtdata->tdata->thread_id].rcv_status = TRANS_DISAGREE;
 895                                 }
 896                         } else {/* If Obj is not locked then lock object */
 897                                 STATUS(((objheader_t *)mobj)) |= LOCK;
 898                                 //TODO Remove this for Testing
 899                                 //randomdelay(); -- Why is this here.  BCD
 900
 901                                 /* Save all object oids that are locked on this machine during this transaction request call */
 902                                 oidlocked[objlocked] = OID(((objheader_t *)mobj));
 903                                 objlocked++;
 904                                 if (version == ((objheader_t *)mobj)->version) { /* Check if versions match */
 905                                         v_matchnolock++;
 906                                 } else { /* If versions don't match ...HARD ABORT */
 907                                         v_nomatch++;
 908                                         /* Send TRANS_DISAGREE to Coordinator */
 909                                         localtdata->tdata->recvmsg[localtdata->tdata->thread_id].rcv_status = TRANS_DISAGREE;
 910                                 }
 911                         }
 912                 }
 913         }
 914
 915         /* Condition to send TRANS_AGREE */
 916         if(v_matchnolock == localtdata->tdata->buffer->f.numread + localtdata->tdata->buffer->f.nummod) {
 917                 localtdata->tdata->recvmsg[localtdata->tdata->thread_id].rcv_status = TRANS_AGREE;
 918         }
 919         /* Condition to send TRANS_SOFT_ABORT */
 920         if((v_matchlock > 0 && v_nomatch == 0) || (objnotfound > 0 && v_nomatch == 0)) {
 921                 localtdata->tdata->recvmsg[localtdata->tdata->thread_id].rcv_status = TRANS_SOFT_ABORT;
 922                 //TODO  currently the only soft abort case that is supported is when object locked by previous
 923                 //transaction => v_matchlock > 0
 924                 //The other case for SOFT ABORT i.e. when object is not found but versions match is not supported
 925                 /* Send number of oids not found and the missing oids if objects are missing in the machine */
 926                 /* TODO Remember to store the oidnotfound for later use
 927                    if(objnotfound != 0) {
 928                    int size = sizeof(unsigned int)* objnotfound;
 929                    }
 930                    */
 931         }
 932
 933         /* Fill out the trans_commit_data_t data structure. This is required for a trans commit process
 934          * if Participant receives a TRANS_COMMIT */
 935         localtdata->transinfo->objlocked = oidlocked;
 936         localtdata->transinfo->objnotfound = oidnotfound;
 937         localtdata->transinfo->modptr = modptr;
 938         localtdata->transinfo->numlocked = objlocked;
 939         localtdata->transinfo->numnotfound = objnotfound;
 940
 941         /* Lock and update count */
 942         //Thread sleeps until all messages from pariticipants are received by coordinator
 943         pthread_mutex_lock(localtdata->tdata->lock);
 944         (*(localtdata->tdata->count))++; /* keeps track of no of messages received by the coordinator */
 945
 946         /* Wake up the threads and invoke decideResponse (once) */
 947         if(*(localtdata->tdata->count) == localtdata->tdata->buffer->f.mcount) {
 948                 decideResponse(localtdata->tdata);
 949                 pthread_cond_broadcast(localtdata->tdata->threshold);
 950         } else {
 951                 pthread_cond_wait(localtdata->tdata->threshold, localtdata->tdata->lock);
 952         }
 953         pthread_mutex_unlock(localtdata->tdata->lock);
 954
 955         /*Based on DecideResponse(), Either COMMIT or ABORT the operation*/
 956         if(*(localtdata->tdata->replyctrl) == TRANS_ABORT){
 957                 if(transAbortProcess(modptr,oidlocked, localtdata->transinfo->numlocked, localtdata->tdata->buffer->f.nummod) != 0) {
 958                         printf("Error in transAbortProcess() %s,%d\n", __FILE__, __LINE__);
 959                         pthread_exit(NULL);
 960                 }
 961         }else if(*(localtdata->tdata->replyctrl) == TRANS_COMMIT){
 962                 if(transComProcess(modptr, localtdata->tdata->buffer->oidmod, localtdata->tdata->buffer->oidcreated, oidlocked, localtdata->tdata->buffer->f.nummod, localtdata->tdata->buffer->f.numcreated, localtdata->transinfo->numlocked) != 0) {
 963                         printf("Error in transComProcess() %s,%d\n", __FILE__, __LINE__);
 964                         pthread_exit(NULL);
 965                 }
 966         }
 967
 968         /* Free memory */
 969         if (localtdata->transinfo->objlocked != NULL) {
 970                 free(localtdata->transinfo->objlocked);
 971                 localtdata->transinfo->objlocked = NULL;
 972         }
 973         if (localtdata->transinfo->objnotfound != NULL) {
 974                 free(localtdata->transinfo->objnotfound);
 975                 localtdata->transinfo->objnotfound = NULL;
 976         }
 977
 978         pthread_exit(NULL);
 979 }
 980 /* This function completes the ABORT process if the transaction is aborting
 981 */
 982 int transAbortProcess(void *modptr, unsigned int *objlocked, int numlocked, int nummod) {
 983         char *ptr;
 984         int i;
 985         objheader_t *tmp_header;
 986         void *header;
 987
 988         /* Set all ref counts as 1 and do garbage collection */
 989         ptr = modptr;
 990         for(i = 0; i< nummod; i++) {
 991                 int tmpsize;
 992                 tmp_header = (objheader_t *)ptr;
 993                 tmp_header->rcount = 0;
 994                 GETSIZE(tmpsize, tmp_header);
 995                 ptr += sizeof(objheader_t) + tmpsize;
 996         }
 997         /* Unlock objects that was locked due to this transaction */
 998         for(i = 0; i< numlocked; i++) {
 999                 if((header = mhashSearch(objlocked[i])) == NULL) {
1000                         printf("mhashsearch returns NULL at %s, %d\n", __FILE__, __LINE__);
1001                         return 1;
1002                 }
1003                 STATUS(((objheader_t *)header)) &= ~(LOCK);
1004         }
1005
1006         /* Send ack to Coordinator */
1007         printf("TRANS_SUCCESSFUL\n");
1008
1009         /*Free the pointer */
1010         ptr = NULL;
1011         return 0;
1012 }
1013
1014 /*This function completes the COMMIT process is the transaction is commiting
1015 */
1016 int transComProcess(void *modptr, unsigned int *oidmod, unsigned int *oidcreated, unsigned int *objlocked, int nummod, int numcreated, int numlocked) {
1017         objheader_t *header;
1018         int i = 0, offset = 0;
1019         char control;
1020
1021         /* Process each modified object saved in the mainobject store */
1022         for(i = 0; i < nummod; i++) {
1023           int tmpsize;
1024                 if((header = (objheader_t *) mhashSearch(oidmod[i])) == NULL) {
1025                         printf("mhashsearch returns NULL at %s, %d\n", __FILE__, __LINE__);
1026                         return 1;
1027                 }
1028                 /* Change reference count of older address and free space in objstr ?? */
1029                 header->rcount = 0;
1030
1031                 /* Change ptr address in mhash table */
1032                 mhashRemove(oidmod[i]); //TODO: this shouldn't be necessary
1033                 mhashInsert(oidmod[i], (((char *)modptr) + offset));
1034                 GETSIZE(tmpsize, header);
1035                 offset += sizeof(objheader_t) + tmpsize;
1036
1037                 /* Update object version number */
1038                 header = (objheader_t *) mhashSearch(oidmod[i]);
1039                 header->version += 1;
1040         }
1041
1042         for (i = 0; i < numcreated; i++)
1043         {
1044                 int tmpsize;
1045                 header = (objheader_t *)(((char *)modptr) + offset);
1046                 mhashInsert(oidcreated[i], (((char *)modptr) + offset));
1047                 GETSIZE(tmpsize, header);
1048                 offset += sizeof(objheader_t) + tmpsize;
1049
1050                 lhashInsert(oidcreated[i], myIpAddr);
1051         }
1052
1053         /* Unlock locked objects */
1054         for(i = 0; i < numlocked; i++) {
1055                 if((header = (objheader_t *) mhashSearch(objlocked[i])) == NULL) {
1056                         printf("mhashsearch returns NULL at %s, %d\n", __FILE__, __LINE__);
1057                         return 1;
1058                 }
1059                 STATUS(header) &= ~(LOCK);
1060         }
1061
1062         //TODO Update location lookup table
1063
1064         /* Send ack to Coordinator */
1065         printf("TRANS_SUCCESSFUL\n");
1066         return 0;
1067 }
1068
1069 /* This function checks if the prefetch oids are same and have same offsets
1070  * for case x.a.b and y.a.b where x and y have same oid's
1071  * or if a.b.c is a subset of x.b.c.d*/
1072 /* check for case where the generated request a.y.z or x.y.z.g then
1073  * prefetch needs to be generated for x.y.z.g  if oid of a and x are same*/
1074 void checkPrefetchTuples(prefetchqelem_t *node) {
1075         int i,j, count,k, sindex, index;
1076         char *ptr, *tmp;
1077         int ntuples, slength;
1078         unsigned int *oid;
1079         short *endoffsets, *arryfields;
1080
1081         /* Check for the case x.y.z and a.b.c are same oids */
1082         ptr = (char *) node;
1083         ntuples = *(GET_NTUPLES(ptr));
1084         oid = GET_PTR_OID(ptr);
1085         endoffsets = GET_PTR_EOFF(ptr, ntuples);
1086         arryfields = GET_PTR_ARRYFLD(ptr, ntuples);
1087         /* Find offset length for each tuple */
1088         int numoffset[ntuples];
1089         numoffset[0] = endoffsets[0];
1090         for(i = 1; i<ntuples; i++) {
1091                 numoffset[i] = endoffsets[i] - endoffsets[i-1];
1092         }
1093         /* Check for redundant tuples by comparing oids of each tuple */
1094         for(i = 0; i < ntuples; i++) {
1095                 if(oid[i] == -1)
1096                         continue;
1097                 for(j = i+1 ; j < ntuples; j++) {
1098                         if(oid[j] == -1)
1099                                 continue;
1100                         /*If oids of tuples match */
1101                         if (oid[i] == oid[j]) {
1102                                 /* Find the smallest offset length of two tuples*/
1103                                 if(numoffset[i] >  numoffset[j]){
1104                                         slength = numoffset[j];
1105                                         sindex = j;
1106                                 }
1107                                 else {
1108                                         slength = numoffset[i];
1109                                         sindex = i;
1110                                 }
1111
1112                                 /* Compare the offset values based on the current indices
1113                                  * break if they do not match
1114                                  * if all offset values match then pick the largest tuple*/
1115
1116                                 if(i == 0) {
1117                                         k = 0;
1118                                         index = endoffsets[j -1];
1119                                         for(count = 0; count < slength; count ++) {
1120                                                 if (arryfields[k] != arryfields[index]) {
1121                                                         break;
1122                                                 }
1123                                                 index++;
1124                                                 k++;
1125                                         }
1126                                 } else {
1127                                         k = endoffsets[i-1];
1128                                         index = endoffsets[j-1];
1129                                         printf("Value of slength = %d\n", slength);
1130                                         for(count = 0; count < slength; count++) {
1131                                                 if(arryfields[k] != arryfields[index]) {
1132                                                         break;
1133                                                 }
1134                                                 index++;
1135                                                 k++;
1136                                         }
1137                                 }
1138
1139                                 if(slength == count) {
1140                                         oid[sindex] = -1;
1141                                 }
1142                         }
1143                 }
1144         }
1145 }
1146
1147 void checkPreCache(prefetchqelem_t *node, int *numoffset, int counter, int loopcount, unsigned int objoid, int index, int iter, int oidnfound) {
1148         char *ptr, *tmp;
1149         int ntuples, i, k, flag;
1150         unsigned int * oid;
1151         short *endoffsets, *arryfields;
1152         objheader_t *header;
1153
1154         ptr = (char *) node;
1155         ntuples = *(GET_NTUPLES(ptr));
1156         oid = GET_PTR_OID(ptr);
1157         endoffsets = GET_PTR_EOFF(ptr, ntuples);
1158         arryfields = GET_PTR_ARRYFLD(ptr, ntuples);
1159
1160         if(oidnfound == 1) {
1161                 if((header = (objheader_t *) prehashSearch(objoid)) == NULL) {
1162                         return;
1163                 } else { //Found in Prefetch Cache
1164                         //TODO Decide if object is too old, if old remove from cache
1165                         tmp = (char *) header;
1166                         /* Check if any of the offset oid is available in the Prefetch cache */
1167                         for(i = counter; i < loopcount; i++) {
1168                                 objoid = *(tmp + sizeof(objheader_t) + arryfields[counter]);
1169                                 if((header = (objheader_t *)prehashSearch(objoid)) != NULL) {
1170                                         flag = 0;
1171                                 } else {
1172                                         flag = 1;
1173                                         break;
1174                                 }
1175                         }
1176                 }
1177         } else {
1178                 for(i = counter; i<loopcount; i++) {
1179                         if((header = (objheader_t *)prehashSearch(objoid)) != NULL) {
1180                                 tmp = (char *) header;
1181                                 objoid = *(tmp + sizeof(objheader_t) + arryfields[index]);
1182                                 flag = 0;
1183                                 index++;
1184                         } else {
1185                                 flag = 1;
1186                                 break;
1187                         }
1188                 }
1189         }
1190
1191         /* If oid not found locally or in prefetch cache then
1192          * assign the latest oid found as the new oid
1193          * and copy left over offsets into the arrayoffsetfieldarray*/
1194         oid[iter] = objoid;
1195         numoffset[iter] = numoffset[iter] - (i+1);
1196         for(k = 0; k < numoffset[iter] ; k++) {
1197                 arryfields[endoffsets[counter]+k] = arryfields[endoffsets[counter]+k+1];
1198         }
1199
1200         if(flag == 0) {
1201                 oid[iter] = -1;
1202                 numoffset[iter] = 0;
1203         }
1204 }
1205
1206 /* This function makes machine piles to be added into the machine pile queue for each prefetch call */
1207 prefetchpile_t *makePreGroups(prefetchqelem_t *node, int *numoffset) {
1208         char *ptr, *tmp;
1209         int ntuples, slength, i, machinenum;
1210         int maxoffset;
1211         unsigned int *oid;
1212         short *endoffsets, *arryfields, *offset;
1213         prefetchpile_t *head = NULL;
1214
1215         /* Check for the case x.y.z and a.b.c are same oids */
1216         ptr = (char *) node;
1217         ntuples = *(GET_NTUPLES(ptr));
1218         oid = GET_PTR_OID(ptr);
1219         endoffsets = GET_PTR_EOFF(ptr, ntuples);
1220         arryfields = GET_PTR_ARRYFLD(ptr, ntuples);
1221
1222         /* Check for redundant tuples by comparing oids of each tuple */
1223         for(i = 0; i < ntuples; i++) {
1224                 if(oid[i] == -1)
1225                         continue;
1226                 /* For each tuple make piles */
1227                 if ((machinenum = lhashSearch(oid[i])) == 0) {
1228                         printf("Error: No such Machine %s, %d\n", __FILE__, __LINE__);
1229                         return NULL;
1230                 }
1231                 /* Insert into machine pile */
1232                 offset = &arryfields[endoffsets[i-1]];
1233                 insertPile(machinenum, oid[i], numoffset[i], offset, &head);
1234         }
1235         return head;
1236 }
1237
1238
1239 /* This function checks if the oids within the prefetch tuples are available locally.
1240  * If yes then makes the tuple invalid. If no then rearranges oid and offset values in
1241  * the prefetchqelem_t node to represent a new prefetch tuple */
1242 prefetchpile_t *foundLocal(prefetchqelem_t *node) {
1243         int ntuples,i, j, k, oidnfound = 0, index, flag;
1244         unsigned int *oid;
1245         unsigned int  objoid;
1246         char *ptr, *tmp;
1247         objheader_t *objheader;
1248         short *endoffsets, *arryfields;
1249         prefetchpile_t *head = NULL;
1250
1251         ptr = (char *) node;
1252         ntuples = *(GET_NTUPLES(ptr));
1253         oid = GET_PTR_OID(ptr);
1254         endoffsets = GET_PTR_EOFF(ptr, ntuples);
1255         arryfields = GET_PTR_ARRYFLD(ptr, ntuples);
1256         /* Find offset length for each tuple */
1257         int numoffset[ntuples];//Number of offsets for each tuple
1258         numoffset[0] = endoffsets[0];
1259         for(i = 1; i<ntuples; i++) {
1260                 numoffset[i] = endoffsets[i] - endoffsets[i-1];
1261         }
1262         for(i = 0; i < ntuples; i++) {
1263                 if(oid[i] == -1)
1264                         continue;
1265                 /* If object found locally */
1266                 if((objheader = (objheader_t*) mhashSearch(oid[i])) != NULL) {
1267                         oidnfound = 0;
1268                         tmp = (char *) objheader;
1269                         /* Find the oid of its offset value */
1270                         if(i == 0)
1271                                 index = 0;
1272                         else
1273                                 index = endoffsets[i - 1];
1274                         for(j = 0 ; j < numoffset[i] ; j++) {
1275                                 objoid = *(tmp + sizeof(objheader_t) + arryfields[index]);
1276                                 /*If oid found locally then
1277                                  *assign the latest oid found as the new oid
1278                                  *and copy left over offsets into the arrayoffsetfieldarray*/
1279                                 oid[i] = objoid;
1280                                 numoffset[i] = numoffset[i] - (j+1);
1281                                 for(k = 0; k < numoffset[i]; k++)
1282                                         arryfields[endoffsets[j]+ k] = arryfields[endoffsets[j]+k+1];
1283                                 index++;
1284                                 /*New offset oid not found */
1285                                 if((objheader = (objheader_t*) mhashSearch(objoid)) == NULL) {
1286                                         flag = 1;
1287                                         checkPreCache(node, numoffset, j, numoffset[i], objoid, index, i, oidnfound);
1288                                         break;
1289                                 } else
1290                                         flag = 0;
1291                         }
1292
1293                         /*If all offset oids are found locally,make the prefetch tuple invalid */
1294                         if(flag == 0) {
1295                                 oid[i] = -1;
1296                                 numoffset[i] = 0;
1297                         }
1298                 } else {
1299                         oidnfound = 1;
1300                         /* Look in Prefetch cache */
1301                         checkPreCache(node, numoffset, 0, numoffset[i], oid[i], 0, i, oidnfound);
1302                 }
1303
1304         }
1305         /* Make machine groups */
1306         head = makePreGroups(node, numoffset);
1307         return head;
1308 }
1309
1310 /* This function is called by the thread calling transPrefetch */
1311 void *transPrefetch(void *t) {
1312         prefetchqelem_t *qnode;
1313         prefetchpile_t *pilehead = NULL;
1314
1315         while(1) {
1316                 /* lock mutex of primary prefetch queue */
1317                 pthread_mutex_lock(&pqueue.qlock);
1318                 /* while primary queue is empty, then wait */
1319                 while((pqueue.front == NULL) && (pqueue.rear == NULL)) {
1320                         pthread_cond_wait(&pqueue.qcond, &pqueue.qlock);
1321                 }
1322
1323                 /* dequeue node to create a machine piles and  finally unlock mutex */
1324                 if((qnode = pre_dequeue()) == NULL) {
1325                         printf("Error: No node returned %s, %d\n", __FILE__, __LINE__);
1326                         pthread_exit(NULL);
1327                 }
1328                 pthread_mutex_unlock(&pqueue.qlock);
1329                 /* Reduce redundant prefetch requests */
1330                 checkPrefetchTuples(qnode);
1331                 /* Check if the tuples are found locally, if yes then reduce them further*/
1332                 /* and group requests by remote machine ids by calling the makePreGroups() */
1333                 pilehead = foundLocal(qnode);
1334
1335                 /* Lock mutex of pool queue */
1336                 pthread_mutex_lock(&mcqueue.qlock);
1337                 /* Update the pool queue with the new remote machine piles generated per prefetch call */
1338                 mcpileenqueue(pilehead);
1339                 /* Broadcast signal on machine pile queue */
1340                 pthread_cond_broadcast(&mcqueue.qcond);
1341                 /* Unlock mutex of  machine pile queue */
1342                 pthread_mutex_unlock(&mcqueue.qlock);
1343                 /* Deallocate the prefetch queue pile node */
1344                 predealloc(qnode);
1345
1346         }
1347 }
1348
1349 /* Each thread in the  pool of threads calls this function to establish connection with
1350  * remote machines, send the prefetch requests and process the reponses from
1351  * the remote machines .
1352  * The thread is active throughout the period of runtime */
1353
1354 void *mcqProcess(void *threadid) {
1355         int tid;
1356         prefetchpile_t *mcpilenode;
1357
1358         tid = (int) threadid;
1359         while(1) {
1360                 /* Lock mutex of mc pile queue */
1361                 pthread_mutex_lock(&mcqueue.qlock);
1362                 /* When mc pile queue is empty, wait */
1363                 while((mcqueue.front == NULL) && (mcqueue.rear == NULL)) {
1364                         pthread_cond_wait(&mcqueue.qcond, &mcqueue.qlock);
1365                 }
1366                 /* Dequeue node to send remote machine connections*/
1367                 if((mcpilenode = mcpiledequeue()) == NULL) {
1368                         printf("Dequeue Error: No node returned %s %d\n", __FILE__, __LINE__);
1369                         pthread_exit(NULL);
1370                 }
1371                 /* Unlock mutex */
1372                 pthread_mutex_unlock(&mcqueue.qlock);
1373
1374                 /*Initiate connection to remote host and send request */
1375                 /* Process Request */
1376                 sendPrefetchReq(mcpilenode, tid);
1377
1378                 /* Deallocate the machine queue pile node */
1379                 mcdealloc(mcpilenode);
1380         }
1381 }
1382
1383 void sendPrefetchReq(prefetchpile_t *mcpilenode, int threadid) {
1384         int sd, i, offset, off, len, endpair, count = 0;
1385         struct sockaddr_in serv_addr;
1386         struct hostent *server;
1387         char machineip[16], control;
1388         objpile_t *tmp;
1389
1390
1391         /* Send Trans Prefetch Request */
1392         if ((sd = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
1393                 perror("Error in socket for TRANS_REQUEST\n");
1394                 return;
1395         }
1396         bzero((char*) &serv_addr, sizeof(serv_addr));
1397         serv_addr.sin_family = AF_INET;
1398         serv_addr.sin_port = htons(LISTEN_PORT);
1399         //serv_addr.sin_addr.s_addr = inet_addr(MACHINE_IP);
1400         midtoIP(mcpilenode->mid ,machineip);
1401         machineip[15] = '\0';
1402         serv_addr.sin_addr.s_addr = inet_addr(machineip);
1403
1404         /* Open Connection */
1405         if (connect(sd, (struct sockaddr *) &serv_addr, sizeof(struct sockaddr)) < 0) {
1406                 perror("Error in connect for TRANS_REQUEST\n");
1407                 close(sd);
1408                 return;
1409         }
1410
1411         /* Send TRANS_PREFETCH control message */
1412         control = TRANS_PREFETCH;
1413         if(send(sd, &control, sizeof(char), MSG_NOSIGNAL) < sizeof(char)) {
1414                 perror("Error in sending prefetch control\n");
1415                 close(sd);
1416                 return;
1417         }
1418
1419         /* Send Oids and offsets in pairs */
1420         tmp = mcpilenode->objpiles;
1421         while(tmp != NULL) {
1422                 off = offset = 0;
1423                 count++;  /* Keeps track of the number of oid and offset tuples sent per remote machine */
1424                 len = sizeof(int) + sizeof(unsigned int) + ((tmp->numoffset) * sizeof(short));
1425                 char oidnoffset[len];
1426                 memcpy(oidnoffset, &len, sizeof(int));
1427                 off = sizeof(int);
1428                 memcpy(oidnoffset + off, &tmp->oid, sizeof(unsigned int));
1429                 off += sizeof(unsigned int);
1430                 for(i = 0; i < tmp->numoffset; i++) {
1431                         memcpy(oidnoffset + off, &tmp->offset[i], sizeof(short));
1432                         off+=sizeof(short);
1433                 }
1434                 if (send(sd, &oidnoffset, sizeof(oidnoffset),MSG_NOSIGNAL) < sizeof(oidnoffset)) {
1435                         perror("Error sending fixed bytes for thread\n");
1436                         close(sd);
1437                         return;
1438                 }
1439                 tmp = tmp->next;
1440         }
1441
1442         /* Send a special char -1 to represent the end of sending oids + offset pair to remote machine */
1443         endpair = -1;
1444         if (send(sd, &endpair, sizeof(int), MSG_NOSIGNAL) < sizeof(int)) {
1445                 perror("Error sending fixed bytes for thread\n");
1446                 close(sd);
1447                 return;
1448         }
1449
1450         /* Get Response from the remote machine */
1451         getPrefetchResponse(count,sd);
1452         close(sd);
1453         return;
1454 }
1455
1456 void getPrefetchResponse(int count, int sd) {
1457         int i = 0, val, n, N, sum, index, objsize;
1458         unsigned int bufsize,oid;
1459         char buffer[RECEIVE_BUFFER_SIZE], control;
1460         char *ptr;
1461         void *modptr, *oldptr;
1462
1463         /* Read  prefetch response from the Remote machine */
1464         if((val = read(sd, &control, sizeof(char))) <= 0) {
1465                 perror("No control response for Prefetch request sent\n");
1466                 return;
1467         }
1468
1469         if(control == TRANS_PREFETCH_RESPONSE) {
1470                 /*For each oid and offset tuple sent as prefetch request to remote machine*/
1471                 while(i < count) {
1472                         sum = 0;
1473                         index = 0;
1474                         /* Read the size of buffer to be received */
1475                         if((N = read(sd, buffer, sizeof(unsigned int))) <= 0) {
1476                                 perror("Size of buffer not recv\n");
1477                                 return;
1478                         }
1479                         memcpy(&bufsize, buffer, sizeof(unsigned int));
1480                         ptr = buffer + sizeof(unsigned int);
1481                         /* Keep receiving the buffer containing oid info */
1482                         do {
1483                                 n = recv((int)sd, (void *)ptr+sum, bufsize-sum, 0);
1484                                 sum +=n;
1485                         } while(sum < bufsize && n != 0);
1486                         /* Decode the contents of the buffer */
1487                         index = sizeof(unsigned int);
1488                         while(index < (bufsize - sizeof(unsigned int))) {
1489                                 if(buffer[index] == OBJECT_FOUND) {
1490                                         /* Increment it to get the object */
1491                                         index += sizeof(char);
1492                                         memcpy(&oid, buffer + index, sizeof(unsigned int));
1493                                         index += sizeof(unsigned int);
1494                                         /* For each object found add to Prefetch Cache */
1495                                         memcpy(&objsize, buffer + index, sizeof(int));
1496                                         index+=sizeof(int);
1497                                         pthread_mutex_lock(&prefetchcache_mutex);
1498                                         if ((modptr = objstrAlloc(prefetchcache, objsize)) == NULL) {
1499                                                 printf("objstrAlloc error for copying into prefetch cache %s, %d\n", __FILE__, __LINE__);
1500                                                 pthread_mutex_unlock(&prefetchcache_mutex);
1501                                                 return;
1502                                         }
1503                                         pthread_mutex_unlock(&prefetchcache_mutex);
1504                                         memcpy(modptr, buffer+index, objsize);
1505                                         index += objsize;
1506                                         /* Insert the oid and its address into the prefetch hash lookup table */
1507                                         /* Do a version comparison if the oid exists */
1508                                         if((oldptr = prehashSearch(oid)) != NULL) {
1509                                                 /* If older version then update with new object ptr */
1510                                                 if(((objheader_t *)oldptr)->version < ((objheader_t *)modptr)->version) {
1511                                                         prehashRemove(oid);
1512                                                         prehashInsert(oid, modptr);
1513                                                 } else if(((objheader_t *)oldptr)->version == ((objheader_t *)modptr)->version) {
1514                                                         /* Add the new object ptr to hash table */
1515                                                         prehashInsert(oid, modptr);
1516                                                 } else { /* Do nothing */
1517                                                         ;
1518                                                 }
1519                                         } else {/*If doesn't no match found in hashtable, add the object ptr to hash table*/
1520                                                 prehashInsert(oid, modptr);
1521                                         }
1522                                         /* Lock the Prefetch Cache look up table*/
1523                                         pthread_mutex_lock(&pflookup.lock);
1524                                         /* Broadcast signal on prefetch cache condition variable */
1525                                         pthread_cond_broadcast(&pflookup.cond);
1526                                         /* Unlock the Prefetch Cache look up table*/
1527                                         pthread_mutex_unlock(&pflookup.lock);
1528                                 } else if(buffer[index] == OBJECT_NOT_FOUND) {
1529                                         /* Increment it to get the object */
1530                                         /* TODO: For each object not found query DHT for new location and retrieve the object */
1531                                         index += sizeof(char);
1532                                         memcpy(&oid, buffer + index, sizeof(unsigned int));
1533                                         index += sizeof(unsigned int);
1534                                         /* Throw an error */
1535                                         printf("OBJECT NOT FOUND.... THIS SHOULD NOT HAPPEN...TERMINATE PROGRAM\n");
1536                                         exit(-1);
1537                                 } else {
1538                                         printf("Error in decoding the index value %s, %d\n",__FILE__, __LINE__);
1539                                         return;
1540                                 }
1541                         }
1542
1543                         i++;
1544                 }
1545         } else
1546                 printf("Error in receving response for prefetch request %s, %d\n",__FILE__, __LINE__);
1547         return;
1548 }
1549
1550 unsigned short getObjType(unsigned int oid)
1551 {
1552         objheader_t *objheader;
1553         unsigned short numoffsets = 0;
1554
1555         if ((objheader = (objheader_t *) mhashSearch(oid)) == NULL)
1556         {
1557                 if ((objheader = (objheader_t *) prehashSearch(oid)) == NULL)
1558                 {
1559                         prefetch(1, &oid, &numoffsets, NULL);
1560                         pthread_mutex_lock(&pflookup.lock);
1561                         while ((objheader = (objheader_t *) prehashSearch(oid)) == NULL)
1562                         {
1563                                 pthread_cond_wait(&pflookup.cond, &pflookup.lock);
1564                         }
1565                         pthread_mutex_unlock(&pflookup.lock);
1566                 }
1567         }
1568
1569         return TYPE(objheader);
1570 }
1571
1572 int startRemoteThread(unsigned int oid, unsigned int mid)
1573 {
1574         int sock;
1575         struct sockaddr_in remoteAddr;
1576         char msg[1 + sizeof(unsigned int)];
1577         int bytesSent;
1578         int status;
1579
1580         if ((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0)
1581         {
1582                 perror("startRemoteThread():socket()");
1583                 return -1;
1584         }
1585
1586         bzero(&remoteAddr, sizeof(remoteAddr));
1587         remoteAddr.sin_family = AF_INET;
1588         remoteAddr.sin_port = htons(LISTEN_PORT);
1589         remoteAddr.sin_addr.s_addr = htonl(mid);
1590
1591         if (connect(sock, (struct sockaddr *)&remoteAddr, sizeof(remoteAddr)) < 0)
1592         {
1593                 printf("startRemoteThread():error %d connecting to %s:%d\n", errno,
1594                         inet_ntoa(remoteAddr.sin_addr), LISTEN_PORT);
1595                 status = -1;
1596         }
1597         else
1598         {
1599                 msg[0] = START_REMOTE_THREAD;
1600                 memcpy(&msg[1], &oid, sizeof(unsigned int));
1601
1602                 bytesSent = send(sock, msg, 1 + sizeof(unsigned int), 0);
1603                 if (bytesSent < 0)
1604                 {
1605                         perror("startRemoteThread():send()");
1606                         status = -1;
1607                 }
1608                 else if (bytesSent != 1 + sizeof(unsigned int))
1609                 {
1610                         printf("startRemoteThread(): error, sent %d bytes\n", bytesSent);
1611                         status = -1;
1612                 }
1613                 else
1614                 {
1615                         status = 0;
1616                 }
1617         }
1618
1619         close(sock);
1620         return status;
1621 }
1622
1623 //TODO: when reusing oids, make sure they are not already in use!
1624 unsigned int getNewOID(void) {
1625         static unsigned int id = 0xFFFFFFFF;
1626
1627         id += 2;
1628         if (id > oidMax || id < oidMin)
1629         {
1630                 id = (oidMin | 1);
1631         }
1632         return id;
1633 }
1634
1635 int processConfigFile()
1636 {
1637         FILE *configFile;
1638         const int maxLineLength = 200;
1639         char lineBuffer[maxLineLength];
1640         char *token;
1641         const char *delimiters = " \t\n";
1642         char *commentBegin;
1643         in_addr_t tmpAddr;
1644
1645         configFile = fopen(CONFIG_FILENAME, "r");
1646         if (configFile == NULL)
1647         {
1648                 printf("error opening %s:\n", CONFIG_FILENAME);
1649                 perror("");
1650                 return -1;
1651         }
1652
1653         numHostsInSystem = 0;
1654         sizeOfHostArray = 8;
1655         hostIpAddrs = calloc(sizeOfHostArray, sizeof(unsigned int));
1656
1657         while(fgets(lineBuffer, maxLineLength, configFile) != NULL)
1658         {
1659                 commentBegin = strchr(lineBuffer, '#');
1660                 if (commentBegin != NULL)
1661                         *commentBegin = '\0';
1662                 token = strtok(lineBuffer, delimiters);
1663                 while (token != NULL)
1664                 {
1665                         tmpAddr = inet_addr(token);
1666                         if ((int)tmpAddr == -1)
1667                         {
1668                                 printf("error in %s: bad token:%s\n", CONFIG_FILENAME, token);
1669                                 fclose(configFile);
1670                                 return -1;
1671                         }
1672                         else
1673                                 addHost(htonl(tmpAddr));
1674                         token = strtok(NULL, delimiters);
1675                 }
1676         }
1677
1678         fclose(configFile);
1679
1680         if (numHostsInSystem < 1)
1681         {
1682                 printf("error in %s: no IP Adresses found\n", CONFIG_FILENAME);
1683                 return -1;
1684         }
1685 #ifdef MAC
1686         myIpAddr = getMyIpAddr("en1");
1687 #else
1688         myIpAddr = getMyIpAddr("eth0");
1689 #endif
1690         myIndexInHostArray = findHost(myIpAddr);
1691         if (myIndexInHostArray == -1)
1692         {
1693                 printf("error in %s: IP Address of eth0 not found\n", CONFIG_FILENAME);
1694                 return -1;
1695         }
1696         oidsPerBlock = (0xFFFFFFFF / numHostsInSystem) + 1;
1697         oidMin = oidsPerBlock * myIndexInHostArray;
1698         if (myIndexInHostArray == numHostsInSystem - 1)
1699                 oidMax = 0xFFFFFFFF;
1700         else
1701                 oidMax = oidsPerBlock * (myIndexInHostArray + 1) - 1;
1702
1703         return 0;
1704 }
1705
1706 void addHost(unsigned int hostIp)
1707 {
1708         unsigned int *tmpArray;
1709
1710         if (findHost(hostIp) != -1)
1711                 return;
1712
1713         if (numHostsInSystem == sizeOfHostArray)
1714         {
1715                 tmpArray = calloc(sizeOfHostArray * 2, sizeof(unsigned int));
1716                 memcpy(tmpArray, hostIpAddrs, sizeof(unsigned int) * numHostsInSystem);
1717                 free(hostIpAddrs);
1718                 hostIpAddrs = tmpArray;
1719         }
1720
1721         hostIpAddrs[numHostsInSystem++] = hostIp;
1722
1723         return;
1724 }
1725
1726 int findHost(unsigned int hostIp)
1727 {
1728         int i;
1729         for (i = 0; i < numHostsInSystem; i++)
1730                 if (hostIpAddrs[i] == hostIp)
1731                         return i;
1732
1733         //not found
1734         return -1;
1735 }
1736