cluster.c 42.7 KB
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514
/*
    clsync - file tree sync utility based on inotify
    
    Copyright (C) 2013  Dmitry Yu Okunev <dyokunev@ut.mephi.ru> 0x8E30679C
    
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.
    
    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
    
    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/*
    Hello, dear developer.

    Cluster technologies are almost always very difficult. So I'll try to
    fill this code with comments. Enjoy ;)

    Also you can ask me directly by e-mail or IRC, if something seems too
    hard.

                                                           -- 0x8E30679C
 */


#ifdef CLUSTER_SUPPORT

#include "common.h"
#include "indexes.h"
#include "error.h"
#include "cluster.h"
#include "sync.h"
#include "calc.h"
#include "malloc.h"

// Global variables. They will be initialized in cluster_init()

#define NODES_ALLOC (MAX(MAXNODES, NODEID_NOID)+1)


int sock_i			= -1;
struct sockaddr_in sa_i		= {0};

int sock_o			= -1;
struct sockaddr_in sa_o		= {0};

ctx_t  *ctx_p		= NULL;
indexes_t  *indexes_p		= NULL;
pthread_t   pthread_cluster	= 0;

nodeinfo_t nodeinfo[NODES_ALLOC]= {{0}};

nodeinfo_t *nodeinfo_my				= NULL;
uint8_t	node_id_my				= NODEID_NOID;
uint8_t node_ids[NODES_ALLOC]			= {0};
unsigned int cluster_timeout			= 0;
uint8_t node_count				= 0;
uint8_t node_online				= 0;

cluster_recvproc_funct_t recvproc_funct[COUNT_CLUSTERCMDID] = {NULL};

window_t window_i = {0};
window_t window_o = {0};

/**
 * @brief 			Adds command (message) to window_p->buffer
 * 
 * @param[in]	clustercmd_p	Pointer to cluster cmd to put into window
 * 
 * @retval	zero		Successful
 * @retval	non-zero	If got error while deleting the message. The error-code is placed into returned value.
 * 
 */

static inline int clustercmd_window_add(window_t *window_p, clustercmd_t *clustercmd_p, GHashTable *serial2queuedpacket_ht) {
#ifdef PARANOID
	if(clustercmd_p->h.src_node_id >= MAXNODES) {
		error("Invalid src_node_id: %i.", clustercmd_p->h.src_node_id);
		return EINVAL;
	}
#endif

	// Checking if there enough window_p->cells allocated
	if(window_p->packets_len >= window_p->size) {
		window_p->size 		+= ALLOC_PORTION;

#		define CXREALLOC(a, size) \
			(typeof(a))xrealloc((char *)(a), (size_t)(size) * sizeof(*(a)))
	
		window_p->packets_id     = CXREALLOC(window_p->packets_id,	window_p->size);
		window_p->occupied_sides = CXREALLOC(window_p->occupied_sides,	window_p->size);
#		undef CXREALLOC
	}

	// Calculating required memory space in buffer for the message
	size_t clustercmd_size = CLUSTERCMD_SIZE(clustercmd_p);
	size_t required_space  = sizeof(clustercmdqueuedpackethdr_t) + clustercmd_size;

	// Searching occupied boundaries in the window_p->buffer
	size_t occupied_left = SIZE_MAX, occupied_right=0;
	int i;
	i = 0;
	while(i < window_p->packets_len) {
		unsigned int window_id;
		window_id  = window_p->packets_id[ i++ ];

		occupied_left  = MIN(occupied_left,  window_p->occupied_sides[window_id].left);
		occupied_right = MAX(occupied_right, window_p->occupied_sides[window_id].right);
	}

	debug(3, "w.size == %u, b_left == %u; b_right == %u; w.buf_size == %u; r_space == %u",
		window_p->size, occupied_left, occupied_right, window_p->buf_size, required_space);

	// Trying to find a space in the buffer to place message
	size_t buf_coordinate = SIZE_MAX;
	if(window_p->packets_len) {
		// Free space from left  (start of buffer)
		size_t free_left  = occupied_left;
		// Free space from right (end of buffer)
		size_t free_right = window_p->buf_size - occupied_right;

		if(free_left  > required_space)
			buf_coordinate = free_left - required_space;
		else
		if(free_right > required_space)
			buf_coordinate   = occupied_right;
		else
		{
			// Not enough space in the window_p->buffer;
			window_p->buf_size += MAX(CLUSTER_WINDOW_BUFSIZE_PORTION, required_space);
			window_p->buf	    = xrealloc(window_p->buf, window_p->buf_size);
			buf_coordinate      = occupied_right;
		}
		debug(3, "f_left == %u; f_right == %u; b_coord == %u; w.buf_size == %u",
			free_left, free_right, buf_coordinate, window_p->buf_size);
	} else {
		buf_coordinate = 0;
		if(window_p->buf_size <= required_space) {
			window_p->buf_size += MAX(CLUSTER_WINDOW_BUFSIZE_PORTION, required_space);
			window_p->buf	    = xrealloc(window_p->buf, window_p->buf_size);
		}
	}

	unsigned int window_id;

	// packet id in window
	window_id = window_p->packets_len;

	// reserving the space in buffer
	window_p->occupied_sides[window_id].left  = buf_coordinate;
	window_p->occupied_sides[window_id].right = buf_coordinate + required_space;

	// placing information into buffer
	clustercmdqueuedpacket_t *queuedpacket_p;

	debug(3, "b_coord == %u", buf_coordinate);
	queuedpacket_p = (clustercmdqueuedpacket_t *)&window_p->buf[buf_coordinate];

	memset(&queuedpacket_p->h,	0,		sizeof(queuedpacket_p->h));
	memcpy(&queuedpacket_p->cmd, 	clustercmd_p, 	clustercmd_size);

	queuedpacket_p->h.window_id  = window_id;

	// remembering new packet
	g_hash_table_insert(serial2queuedpacket_ht, GINT_TO_POINTER(clustercmd_p->h.serial), queuedpacket_p);
	window_p->packets_id[window_p->packets_len++] = window_id;

	return 0;
}


/**
 * @brief 			Removes command (message) from window_p->buffer
 * 
 * @param[in]	queuedpacket_p	Pointer to queuedpacket structure of the command (message)
 * 
 * @retval	zero		Successful
 * @retval	non-zero	If got error while deleting the message. The error-code is placed into returned value.
 * 
 */

static inline int clustercmd_window_del(window_t *window_p, clustercmdqueuedpacket_t *queuedpacket_p, GHashTable *serial2queuedpacket_ht) {
#ifdef PARANOID
	if(!window_p->size) {
		error("window not allocated.");
		return EINVAL;
	}
	if(!window_p->packets_len) {
		error("there already no packets in the window.");
		return EINVAL;
	}
#endif

	unsigned int window_id_del  =  queuedpacket_p->h.window_id;
	unsigned int window_id_last = --window_p->packets_len;

	// Forgeting the packet

	// 	Moving the last packet into place of deleting packet, to free the tail in "window_p->packets_id" and "window_p->occupied_sides"
	if(window_id_del != window_id_last) {
		debug(3, "%i -> %i", window_id_last, window_id_del);

		window_p->packets_id[window_id_del] = window_p->packets_id[window_id_last];

		memcpy(&window_p->occupied_sides[window_id_del], &window_p->occupied_sides[window_id_last], sizeof(window_p->occupied_sides[window_id_del]));
	}

	// 	Removing from hash table
	g_hash_table_remove(serial2queuedpacket_ht, GINT_TO_POINTER(queuedpacket_p->cmd.h.serial));

	return 0;
}


/**
 * @brief 			Calculates Adler32 for clustercmd
 * 
 * @param[in]	clustercmd_p	Pointer to clustercmd
 * @param[out]	clustercmdadler32_p Pointer to structure to return value(s)
 * 
 * @retval	zero		On successful calculation
 * @retval	non-zero	On error. Error-code is placed into returned value.
 * 
 */

int clustercmd_adler32_calc(clustercmd_t *clustercmd_p, clustercmdadler32_t *clustercmdadler32_p, adler32_calc_t flags) {
	debug(15, "(%p, %p, 0x%x)", clustercmd_p, clustercmdadler32_p, flags);

	if (flags & ADLER32_CALC_DATA) {
		uint32_t adler32;

		uint32_t size = clustercmd_p->h.data_len;
		char    *ptr  = clustercmd_p->data.p;

		// Calculating
		adler32 = adler32_calc((unsigned char *)ptr, CLUSTER_PAD(size));
		debug(20, "dat: 0x%x", adler32);

		// Ending
		clustercmdadler32_p->dat = adler32 ^ 0xFFFFFFFF;
	}

	if (flags & ADLER32_CALC_HEADER) {
		uint32_t adler32;
		clustercmdadler32_t adler32_save;

		// Preparing
		memcpy(&adler32_save.hdr,		&clustercmd_p->h.adler32.hdr,	sizeof(clustercmd_p->h.adler32.hdr));
		memset(&clustercmd_p->h.adler32.hdr, 	0,				sizeof(clustercmd_p->h.adler32.hdr));
		adler32 = 0xFFFFFFFF;

		uint32_t size = sizeof(clustercmdhdr_t);
		char    *ptr  = (char *)&clustercmd_p->h;

		// Calculating
		adler32 = adler32_calc((unsigned char *)ptr, size);
		debug(20, "hdr: 0x%x", adler32);

		// Ending
		memcpy(&clustercmd_p->h.adler32.hdr, &adler32_save.hdr, sizeof(clustercmd_p->h.adler32.hdr));
		clustercmdadler32_p->hdr = adler32 ^ 0xFFFFFFFF;
	}

	return 0;
}

/**
 * @brief 			Changes information about node's status in nodeinfo[] and updates connected information.
 * 
 * @param[in]	node_id		node_id of the node.
 * @param[in]	node_status	New node status.
 * 
 * @retval	zero		Successful
 * @retval	non-zero	If got error while changing the status. The error-code is placed into returned value.
 * 
 */

int node_status_change(uint8_t node_id, uint8_t node_status) {
	uint8_t node_status_old = nodeinfo[node_id].status;
	nodeinfo_t *nodeinfo_p = &nodeinfo[node_id];

	if((node_status == NODESTATUS_DOESNTEXIST) && (node_status_old != NODESTATUS_DOESNTEXIST)) {
		node_count--;

		node_ids[nodeinfo_p->num] = node_ids[node_count];
		g_hash_table_destroy(nodeinfo_p->modtime_ht);
		g_hash_table_destroy(nodeinfo_p->serial2queuedpacket_ht);

#ifdef VERYPARANOID
		memset(nodeinfo_p, 0, sizeof(*nodeinfo_p));
#endif
		return 0;
	}

	if(node_status == node_status_old)
		return 0;

	switch(node_status_old) {
		case NODESTATUS_DOESNTEXIST:
			nodeinfo_p->id			   = node_id;
			nodeinfo_p->num			   = node_count;
			nodeinfo_p->last_serial		   = -1;
			nodeinfo_p->modtime_ht 		   = g_hash_table_new_full(g_str_hash,	  g_str_equal,	  free, 0);
			nodeinfo_p->serial2queuedpacket_ht = g_hash_table_new_full(g_direct_hash, g_direct_equal, 0,    0);

			node_ids[node_count] = node_id;

			node_count++;
#ifdef PARANOID
			if(node_status == NODESTATUS_OFFLINE)
				break; // In case of NODESTATUS_DOESNTEXIST -> NODESTATUS_OFFLINE, node_online should be increased
#endif
		case NODESTATUS_OFFLINE:
			node_online++;
			break;
		default:
			if(node_status == NODESTATUS_OFFLINE)
				node_online--;
			break;
	}

	nodeinfo[node_id].status = node_status;

	return 0;
}


/**
 * @brief 			Sends message to another nodes of the cluster.
 * 
 * @param[in]	clustercmd_p	Command structure pointer.
 *
 * @retval	zero 		Successfully send.
 * @retval	non-zero 	Got error, while sending.
 * 
 */

int _cluster_send(clustercmd_t *clustercmd_p) {
	clustercmd_p->h.src_node_id = node_id_my;
	SAFE (clustercmd_adler32_calc(clustercmd_p, &clustercmd_p->h.adler32, ADLER32_CALC_ALL), return _SAFE_rc );

	debug(3, "Sending: "
		"{h.dst_node_id: %u, h.src_node_id: %u, cmd_id: %u, adler32.hdr: %p, adler32.dat: %p, data_len: %u}",
		clustercmd_p->h.dst_node_id, clustercmd_p->h.src_node_id, clustercmd_p->h.cmd_id,
		(void *)(long)clustercmd_p->h.adler32.hdr, (void *)(long)clustercmd_p->h.adler32.dat,
		clustercmd_p->h.data_len);

	nodeinfo_t *nodeinfo_p;
	nodeinfo_p = &nodeinfo[clustercmd_p->h.dst_node_id];

	// Checking if the node online
	switch (nodeinfo_p->status) {
		case NODESTATUS_DOESNTEXIST:
		case NODESTATUS_OFFLINE:
			debug(1, "There's no online node with id %u. Skipping sending.", clustercmd_p->h.dst_node_id);
			return EADDRNOTAVAIL;
		default:
			break;
	}

	// Putting the message into an output window
	if (nodeinfo_my != NULL)
		clustercmd_window_add(&window_o, clustercmd_p, nodeinfo_my->serial2queuedpacket_ht);

	// Sending the message
	debug(10, "sendto(%p, %p, %i, 0, %p, %i)", sock_o, clustercmd_p, CLUSTERCMD_SIZE_PADDED(clustercmd_p), &sa_o, sizeof(sa_o));
	debug(50, "clustercmd_p->data.p[0] == 0x%x", clustercmd_p->data.p[0]);
	critical_on (sendto(sock_o, clustercmd_p, CLUSTERCMD_SIZE_PADDED(clustercmd_p), 0, &sa_o, sizeof(sa_o)) == -1);

	// Finishing
	return 0;
}

static inline int cluster_send(clustercmd_t *clustercmd_p) {
	int rc;

	rc = _cluster_send(clustercmd_p);
	debug(10, "__________________sent___________________ %i", rc);

	return rc;
}

/**
 * @brief 			Sets message processing functions for cluster_recv_proc() function for specified command type
 * 
 * @param[in]	cmd_id		The command type
 * @param[in]	procfunct	The processing function for messages with specified cmd_id
 * 
 * @retval	zero		Successful
 * @retval	non-zero	If got error while setting processing function. The error-code is placed into returned value.
 * 
 */

static inline int cluster_recv_proc_set(clustercmd_id_t cmd_id, cluster_recvproc_funct_t procfunct) {
	recvproc_funct[cmd_id] = procfunct;

	return 0;
}


/**
 * @brief 			Safe wrapper for recvfrom() function
 * 
 * @param[in]	sock		The socket descriptor
 * @param[in]	buf		Pointer to buffer
 * @param[in]	size		Amount of bytes to read
 * 
 * @retval	zero		Successful
 * @retval	non-zero	If got error while read()-ing. The error-code is placed into returned value. "-1" means that message is too short.
 * 
 */

static inline int cluster_read(int sock, void *buf, size_t size, cluster_read_flags_t flags) {
	static struct in_addr last_addr = {0};
	struct sockaddr_in sa_in;
	size_t sa_in_len = sizeof(sa_in);
	debug(20, "%i, %p, %i, 0x%x", sock, buf, size, flags);

	if (!size)
		return 0;

	int readret = recvfrom(sock, buf, size, MSG_WAITALL, (struct sockaddr *)&sa_in, (socklen_t * restrict)&sa_in_len);
	debug(30, "recvfrom(%i, %p, %i, 0x%x, %p, %p) -> %i", sock, buf, size, MSG_WAITALL, &sa_in, &sa_in_len, readret);
	if (flags & CLREAD_CONTINUE) {
		if(memcmp(&last_addr, &sa_in.sin_addr, sizeof(last_addr))) {
			debug(1, "Get message from wrong source (%s != %s). Skipping it :(.", inet_ntoa(sa_in.sin_addr), inet_ntoa(last_addr));
			size = 0;
			return 0;
		}
	}
	debug(50, "*buf == 0x%x", *(char *)buf);
	memcpy(&last_addr, &sa_in.sin_addr, sizeof(last_addr));

#ifdef PARANOID
	if (!readret) {
		error("recvfrom() returned 0. This shouldn't happend. Exit.");
		return EINVAL;
	}
#endif
	if (readret < 0) {
		error("recvfrom() returned %i. "
			"Seems, that something wrong with network socket.", 
			readret);
		return errno != -1 ? errno : -2;
	}

	debug(2, "Got message from %s (len: %i, expected: %i).", inet_ntoa(sa_in.sin_addr), readret, size);

	if (readret < size) {
		// Too short message
		error("Warning: cluster_read(): Got too short message from node. Ignoring it.");
		return -1;
	}

	// Incorrect size of data?
	if (readret & 0x3) {
		error("Warning: cluster_recv(): Received frame of size %i (not a multiple of 4). Ignoring it.", readret);
		return 0;
	}

	return 0;
}


/**
 * @brief 			Sends packet-reject notification
 * 
 * @param[in]	clustercmd_p	Pointer to clustercmd that will be rejected
 * @param[in]	reason		Reason why the clustercmd is denied
 * 
 * @retval	zero		Successful
 * @retval	non-zero	If got error while read()-ing. The error-code is placed into returned value. "-1" means that message is too short.
 * 
 */

static inline int clustercmd_reject(clustercmd_t *clustercmd_p, uint8_t reason) {
	clustercmd_t *clustercmd_rej_p 		= CLUSTER_ALLOCA(clustercmd_rej_t, 0);
	clustercmd_rej_p->h.dst_node_id 	= clustercmd_p->h.src_node_id;
	clustercmd_rej_p->data.rej.serial 	= clustercmd_p->h.serial;
	clustercmd_rej_p->data.rej.reason 	= reason;

	return cluster_send(clustercmd_rej_p);
}


#define CLUSTER_RECV_RETURNMESSAGE(clustercmd_p) {\
		last_serial      = (clustercmd_p)->h.serial;\
		last_src_node_id = (clustercmd_p)->h.src_node_id;\
		if(clustercmd_pp != NULL)\
			*clustercmd_pp = (clustercmd_p);\
		return 1;\
}
/**
 * @brief 			Receives message from another nodes of the cluster. (not thread-safe)
 * 
 * @param[out]	clustercmd_pp	Pointer to command structure pointer. It will be re-allocated every time when size is not enough. Allocated space will be reused on next calling.
 * @param[i/o]	timeout_p	Pointer to timeout (in milliseconds). Timeout is assumed zero if the pointer is NULL. After waiting the event timeout value will be decreased on elapsed time.
 * 
 * @retval	1		If there's new message.
 * @retval	0		If there's no new messages.
 * @retval	-1		If got error while receiving. The error-code is placed into "errno".
 * 
 */

static int _cluster_recv(clustercmd_t **clustercmd_pp, unsigned int *timeout_p) {
	static clustercmd_t *clustercmd_p=NULL;
	static size_t size=0;
	static uint8_t  last_src_node_id = NODEID_NOID;
	static uint32_t last_serial	 = 0;
	int timeout;

	// Getting the timeout
	timeout = (timeout_p == NULL ? 0 : *timeout_p);

	if(!size) {
		size = BUFSIZ;
		clustercmd_p = (clustercmd_t *)xmalloc(size);
	}

	// Checking if there message is waiting in the window
	if(last_src_node_id != NODEID_NOID) {
		nodeinfo_t *nodeinfo_p = &nodeinfo[last_src_node_id];

		clustercmdqueuedpacket_t *clustercmdqueuedpacket_p = (clustercmdqueuedpacket_t *)
			g_hash_table_lookup(nodeinfo_p->serial2queuedpacket_ht, GINT_TO_POINTER(last_serial+1));

		if(clustercmdqueuedpacket_p != NULL)
			CLUSTER_RECV_RETURNMESSAGE(&clustercmdqueuedpacket_p->cmd);
	}

	// Checking if there any event on read socket
	//	select()
	struct timeval tv;

	fd_set rfds;
	FD_ZERO(&rfds);
	FD_SET(sock_i, &rfds);

	tv.tv_sec  = timeout / 1000;
	tv.tv_usec = timeout % 1000;

	int selret = select(sock_i+1, &rfds, NULL, NULL, &tv);

	// 	Remembering the rest part of timeout
	if(timeout_p != NULL)
		*timeout_p = tv.tv_sec * 1000 + tv.tv_usec / 1000;

	//	processing select()'s retuned value
	if(selret <  0) {
		error("got error while select().");
		return 0;
	}
	if(selret == 0) {
		debug(3, "no new messages.");
		return 0;
	}
	debug(3, "got new message(s).");

	// Reading new message's header
	clustercmdadler32_t adler32;
	//clustercmd_t *clustercmd_p = (clustercmd_t *)mmap(NULL, sizeof(clustercmdhdr_t), PROT_NONE, 
	//	MAP_PRIVATE, sock, 0);
	int ret;
	if ((ret=cluster_read(sock_i, (void *)clustercmd_p, sizeof(clustercmdhdr_t), CLREAD_NONE))) {
		if(ret == -1) return 0; // Invalid message? Skipping.

		error("Got error from cluster_read().");
		errno = ret;
		return -1;
	}

	debug(3, "Received: {h.dst_node_id: %u, h.src_node_id: %u, cmd_id: %u,"
		" serial: %u, adler32: {0x%x, 0x%x}, data_len: %u}, "
		"timeout: %u -> %u",
		clustercmd_p->h.dst_node_id, clustercmd_p->h.src_node_id, 
		clustercmd_p->h.cmd_id, clustercmd_p->h.serial,
		clustercmd_p->h.adler32.hdr, clustercmd_p->h.adler32.dat,
		clustercmd_p->h.data_len, *timeout_p,
		timeout);

	// Checking adler32 of packet headers.
	clustercmd_adler32_calc(clustercmd_p, &adler32, ADLER32_CALC_HEADER);
	if (adler32.hdr != clustercmd_p->h.adler32.hdr) {
		debug(1, "hdr-adler32 mismatch: %p != %p.", 
			(void*)(long)clustercmd_p->h.adler32.hdr, (void*)(long)adler32.hdr);

		if((ret=clustercmd_reject(clustercmd_p, REJ_ADLER32MISMATCH)) != EADDRNOTAVAIL) {
			error("Got error while clustercmd_reject().");
			errno = ret;
			return -1;
		}
	}

	// Checking src_node_id and dst_node_id
	uint8_t src_node_id = clustercmd_p->h.src_node_id;
	uint8_t dst_node_id = clustercmd_p->h.dst_node_id;

	// 	Packet from registering node?
	if (src_node_id == NODEID_NOID) {
		// 	Wrong command from registering node?
		if (clustercmd_p->h.cmd_id != CLUSTERCMDID_GETMYID) {
			error("Warning: cluster_recv(): Got non getmyid packet from NOID node. Ignoring the packet.");
			return 0;
		}
		if (clustercmd_p->h.serial != 0) {
			error("Warning: cluster_recv(): Got packet with non-zero serial from NOID node. Ignoring the packet.");
			return 0;
		}
	} else
	// 	Wrong src_node_id?
	if (src_node_id >= MAXNODES) {
		error("Warning: cluster_recv(): Invalid h.src_node_id: %i >= "XTOSTR(MAXNODES)"",
			src_node_id);
		return 0;
	}

	// 	Is this broadcast message?
	if (dst_node_id == NODEID_NOID) {
		// CODE HERE
	} else
	//	Wrong dst_node_id?
	if (dst_node_id >= MAXNODES) {
		error("Warning: cluster_recv(): Invalid h.dst_node_id: %i >= "XTOSTR(MAXNODES)"", 
			dst_node_id);
		return 0;
	}

	// Seems, that headers are correct. Continuing.

	// Paranoid routines
	//	The message from us? Something wrong if it is.
#ifdef PARANOID
	if((clustercmd_p->h.src_node_id == node_id_my) && (node_id_my != NODEID_NOID)) {
#ifdef VERYPARANOID
		error("clustercmd_p->h.src_node_id == node_id_my (%i == %i)."
			" Exit.", clustercmd_p->h.src_node_id, node_id_my);
		return EINVAL;
#else
		error("Warning: cluster_recv(): clustercmd_p->h.src_node_id == node_id_my (%i != %i)."
			" Ignoring the command.", clustercmd_p->h.src_node_id, node_id_my);
		clustercmd_p = NULL;
		return 0;
#endif
	}
#endif

	nodeinfo_t *nodeinfo_p = &nodeinfo[src_node_id];

	// Not actual packet?
	long serial_diff = clustercmd_p->h.serial - nodeinfo_p->last_serial;
	debug(10, "serial_diff == %i", serial_diff);
	if (serial_diff <= 0 || serial_diff > CLUSTER_WINDOW_PCKTLIMIT) {
		debug(1, "Ignoring packet (serial %i) from %i due to serial_diff: 0 <= || > %i", 
			clustercmd_p->h.serial, src_node_id, serial_diff, CLUSTER_WINDOW_PCKTLIMIT);
		return 0;
	}

	// Is this misordered packet?
	if (clustercmd_p->h.serial != nodeinfo_p->last_serial + 1) {
		clustercmd_window_add(&window_i, clustercmd_p, nodeinfo_p->serial2queuedpacket_ht);
		return 0;
	}

	// Is this the end of packet (packet without data)
	if (clustercmd_p->h.data_len == 0)
		CLUSTER_RECV_RETURNMESSAGE(clustercmd_p);

	// Too big data?
	if (clustercmd_p->h.data_len > CLUSTER_PACKET_MAXSIZE) {
		error("Warning: cluster_recv(): Got too big message from node %i. Ignoring it.",
			src_node_id);
		return 0;
	}

	// Need more space for this packet?
	if (CLUSTERCMD_SIZE(clustercmd_p) > size) {
		size   = CLUSTERCMD_SIZE(clustercmd_p);
		clustercmd_p = (clustercmd_t *)xrealloc((char *)clustercmd_p, size);
	}

	// Reading the data
	if ((ret=cluster_read(sock_i, (void *)clustercmd_p->data.p, CLUSTER_PAD(clustercmd_p->h.data_len), CLREAD_CONTINUE))) {
		if (ret == -1) return 0;

		error("Got error from cluster_read().");
		errno = ret;
		return -1;
	}

	// Checking adler32 of packet data.
	clustercmd_adler32_calc(clustercmd_p, &adler32, ADLER32_CALC_DATA);
	if (adler32.dat != clustercmd_p->h.adler32.dat) {
		debug(1, "dat-adler32 mismatch: %p != %p.", 
			(void*)(long)clustercmd_p->h.adler32.dat, (void*)(long)adler32.dat);

		if ((ret=clustercmd_reject(clustercmd_p, REJ_ADLER32MISMATCH)) != EADDRNOTAVAIL) {
			error("Got error while clustercmd_reject().");
			errno = ret;
			return -1;
		}
	}

	CLUSTER_RECV_RETURNMESSAGE(clustercmd_p);
}

static inline int cluster_recv(clustercmd_t **clustercmd_pp, unsigned int *timeout_p) {
	int rc;

	rc = _cluster_recv(clustercmd_pp, timeout_p);
	debug(10, "__________________recv___________________ %i", rc);

	return rc;
}


/**
 * @brief 			(hsyncop) Reads messages for time "_timeout" and proceeding them to recvproc_funct[] functions
 * 
 * @param[in]	_timeout	How long to wait messages (totally)
 * 
 * @retval	zero		Successful
 * @retval	non-zero	If got error while reading or processing messages. The error-code is placed into returned value.
 * 
 */

 int cluster_recv_proc(unsigned int _timeout) {
	debug(3, "cluster_recv_proc(%i)", _timeout);
	clustercmd_t *clustercmd_p = NULL;
	int ret;
	unsigned int timeout = _timeout;
	while((ret=cluster_recv(&clustercmd_p, &timeout))) {
		// Exit if error
		if(ret == -1) {
			error("Got error while cluster_recv(): %s (%i).");
			return errno;
		}

		// If we have appropriate callback function, then call it! :)
		if(recvproc_funct[clustercmd_p->h.cmd_id])
			if((ret=recvproc_funct[clustercmd_p->h.cmd_id](clustercmd_p))) {
				error("Got error from recvproc_funct[%i]: %s (%i)", 
					clustercmd_p->h.cmd_id);
				return ret;
			}
	}

	return 0;
}


/**
 * @brief 			recvproc-function for ACK-messages
 * 
 * @param[in] 	clustercmd_p 	Pointer to clustercmd
 * @param[in] 	arg_p		Pointer to argument
 *
 * @retval	zero 		Successfully initialized.
 * @retval	non-zero 	Got error, while initializing.
 * 
 */

static int cluster_recvproc_ack(clustercmd_t *clustercmd_p) {

	uint32_t cmd_serial_ack = clustercmd_p->data.ack.serial;

	clustercmdqueuedpacket_t *queuedpacket_p = 
		(clustercmdqueuedpacket_t *)g_hash_table_lookup(nodeinfo_my->serial2queuedpacket_ht, GINT_TO_POINTER(cmd_serial_ack));

	if(queuedpacket_p == NULL)
		return 0;

	uint8_t node_id_from = clustercmd_p->h.src_node_id;

	if(! queuedpacket_p->h.w.o.ack_from[node_id_from]) {
		queuedpacket_p->h.w.o.ack_count++;
		queuedpacket_p->h.w.o.ack_from[node_id_from]++;

		if(queuedpacket_p->h.w.o.ack_count == node_count-1)
			clustercmd_window_del(&window_o, queuedpacket_p, nodeinfo_my->serial2queuedpacket_ht);
	}

	return 0;
}


/**
 * @brief 			Sets message processing functions for cluster_recv_proc() function for specified command type
 * 
 * @param[in]	cmd_id		The command type
 * @param[in]	procfunct	The processing function for messages with specified cmd_id
 * 
 * @retval	zero		Successful
 * @retval	non-zero	If got error while setting processing function. The error-code is placed into returned value.
 * 
 */

int cluster_io_init() {
	cluster_recv_proc_set(CLUSTERCMDID_ACK, cluster_recvproc_ack);
	return 0;
}


/**
 * @brief 			Antagonist of cluster_recv_proc_init() function. Freeing everything what was allocated in cluster_recv_proc_init()
 * 
 * @retval	zero 		Successfully initialized
 * @retval	non-zero 	Got error, while initializing
 * 
 */

int cluster_io_deinit() {

	if(window_i.buf_size) {
#ifdef PARANOID
		if(window_i.buf == NULL) {
			error("window_i.buf_size != 0, but window_i.buf == NULL.");
		} else
#endif
		free(window_i.buf);
	}

	if(window_o.buf_size) {
#ifdef PARANOID
		if(window_o.buf == NULL) {
			error("window_o.buf_size != 0, but window_o.buf == NULL.");
		} else
#endif
		free(window_o.buf);
	}

	return 0;
}

/**
 * @brief 			recvproc-function for setid-messages
 * 
 * @param[in] 	clustercmd_p 	Pointer to clustercmd
 * @param[in] 	arg_p		Pointer to argument
 *
 * @retval	zero 		Successfully initialized.
 * @retval	non-zero 	Got error, while initializing.
 * 
 */

static int cluster_recvproc_setid(clustercmd_t *clustercmd_p) {
	static time_t updatets = 0;

	// 	Is this the most recent information? Skipping if not.
	clustercmd_setiddata_t *data_setid_p = &clustercmd_p->data.setid;
	if(!(data_setid_p->updatets > updatets))
		return 0;

	// 	Is the node name length in message equals to our node name length? Skipping if not.
	uint32_t recv_nodename_len;
	recv_nodename_len = CLUSTER_RESTDATALEN(clustercmd_p, clustercmd_setiddata_t);
	if(recv_nodename_len != ctx_p->cluster_nodename_len)
		return 0;

	// 	Is the node name equals to ours? Skipping if not.
	if(memcmp(data_setid_p->node_name, ctx_p->cluster_nodename, recv_nodename_len))
		return 0;

	//	Remembering the node that answered us
	node_status_change(clustercmd_p->h.src_node_id, NODESTATUS_SEEMSONLINE);

	// 	Seems, that somebody knows our node id, remembering it.
	node_id_my  = clustercmd_p->h.dst_node_id;
	updatets    = data_setid_p->updatets;

	return 0;
}


extern int cluster_loop();
/**
 * @brief 			Initializes cluster subsystem.
 * 
 * @param[in] 	_ctx_p 	Pointer to "glob" variable, defined in main().
 * @param[in] 	_indexes_p	Pointer to "indexes" variable, defined in sync_run().
 *
 * @retval	zero 		Successfully initialized.
 * @retval	non-zero 	Got error, while initializing.
 * 
 */

int cluster_init(ctx_t *_ctx_p, indexes_t *_indexes_p) {
	int ret;

	// Preventing double initializing
	if(ctx_p != NULL) {
		error("cluster subsystem is already initialized.");
		return EALREADY;
	}

	// Initializing global variables, pt. 1
	ctx_p	= _ctx_p;
	indexes_p	= _indexes_p;
	cluster_timeout	= ctx_p->cluster_timeout;
	node_status_change(NODEID_NOID, NODESTATUS_ONLINE);

	// Initializing network routines

	// 	Input socket

	//		Creating socket

	sock_i = socket(AF_INET, SOCK_DGRAM, 0);
	if(sock_i < 0) {
		error("Cannot create socket for input traffic");
		return errno;
	}

	// 		Enable SO_REUSEADDR to allow multiple instances of this application to receive copies
	// 		of the multicast datagrams.

	int reuse = 1;
	if(setsockopt(sock_i, SOL_SOCKET, SO_REUSEADDR,(char *)&reuse, sizeof(reuse)) < 0) {
		error("Got error while setsockopt()");
		return errno;
	}

	//		Binding

	sa_i.sin_family		= AF_INET;
	sa_i.sin_port 		= htons(ctx_p->cluster_mcastipport);
	sa_i.sin_addr.s_addr	= INADDR_ANY;

	if(bind(sock_i, (struct sockaddr*)&sa_i, sizeof(sa_i))) {
		error("Got error while bind()");
		return errno;
	}

	//		Joining to multicast group

	struct ip_mreq group;
	group.imr_interface.s_addr = inet_addr(ctx_p->cluster_iface);
	group.imr_multiaddr.s_addr = inet_addr(ctx_p->cluster_mcastipaddr);

	if(setsockopt(sock_i, IPPROTO_IP, IP_ADD_MEMBERSHIP, 
				(char *)&group, sizeof(group)) < 0) {
		error("Cannot setsockopt() to enter to membership %s -> %s",
			ctx_p->cluster_iface, ctx_p->cluster_mcastipaddr);
		return errno;
	}

	//	Output socket

	//		Creating socket

	sock_o = socket(AF_INET, SOCK_DGRAM, 0);
	if(sock_o < 0) {
		error("Cannot create socket for output traffic");
		return errno;
	}
	
	//		Initializing the group sockaddr structure

	sa_o.sin_family		= AF_INET;
	sa_o.sin_port 		= htons(ctx_p->cluster_mcastipport);
	sa_o.sin_addr.s_addr	= inet_addr(ctx_p->cluster_mcastipaddr);

	//		Disable looping back output datagrams

	{
		char loopch = 0;
		if(setsockopt(sock_o, IPPROTO_IP, IP_MULTICAST_LOOP, (char *)&loopch, sizeof(loopch))<0) {
			error("Cannot disable loopback for output socket.");
			return errno;
		}
	}

	//		Setting local interface for output traffic

	{
		struct in_addr addr_o;
		addr_o.s_addr = inet_addr(ctx_p->cluster_iface);
		if(setsockopt(sock_o, IPPROTO_IP, IP_MULTICAST_IF, &addr_o, sizeof(addr_o)) < 0) {
			error("Cannot set local interface for outbound traffic");
			return errno;
		}
	}


	// Initializing another routines
	cluster_io_init();

	// Getting my ID in the cluster

	//	Trying to preserve my node_id after restart. :)
	//	Asking another nodes about my previous node_id
	{
		debug(15, "Preparing a message with my nodename == \"%s\" (%i)", ctx_p->cluster_nodename, ctx_p->cluster_nodename_len);

		clustercmd_t *clustercmd_p = CLUSTER_ALLOCA(clustercmd_getmyid_t, ctx_p->cluster_nodename_len);

		clustercmd_p->h.data_len = ctx_p->cluster_nodename_len;
		memcpy(clustercmd_p->data.getmyid.node_name, ctx_p->cluster_nodename, clustercmd_p->h.data_len+1);

		clustercmd_p->h.cmd_id      = CLUSTERCMDID_GETMYID;
		clustercmd_p->h.dst_node_id = NODEID_NOID; // broadcast
		if ((ret=cluster_send(clustercmd_p)))
			return ret;
	}

	//	Processing answers
	cluster_recv_proc_set(CLUSTERCMDID_SETID, cluster_recvproc_setid);

	if ((ret=cluster_recv_proc(cluster_timeout)))
		return ret;

	debug(3, "After communicating with others, my node_id is %i.", node_id_my);

	//	Getting free node_id if nobody said us the certain value (see above).
	if (node_id_my == NODEID_NOID) {
		int i=0;
		while (i<MAXNODES) {
			if (nodeinfo[i].status == NODESTATUS_DOESNTEXIST) {
				node_id_my = i;
				break;
			}
			i++;
		}
		debug(3, "I was have to set my node_id to %i.", node_id_my);
	}

	//	If there's no free id-s, then exit :(
	if(node_id_my == NODEID_NOID) {
		error("Cannot find free node ID. Seems, that all %i ID-s are already occupied.");
		return ENOMEM;
	}

	// Registering in the cluster

	// 	Sending registration information
	node_status_change(node_id_my, NODESTATUS_SEEMSONLINE);
	{
		clustercmd_t *clustercmd_p = CLUSTER_ALLOCA(clustercmd_reg_t, ctx_p->cluster_nodename_len);
		clustercmd_reg_t *data_reg_p = &clustercmd_p->data.reg;

		memcpy(data_reg_p->node_name, ctx_p->cluster_nodename, ctx_p->cluster_nodename_len+1);

		clustercmd_p->h.data_len    = ctx_p->cluster_nodename_len+1;
		clustercmd_p->h.cmd_id      = CLUSTERCMDID_REG;
		clustercmd_p->h.dst_node_id = NODEID_NOID; // broadcast
		if((ret=cluster_send(clustercmd_p)))
			return ret;
	}

	// 	Getting answers
	if((ret=cluster_recv_proc(cluster_timeout)))
		return ret;

	node_status_change(node_id_my, NODESTATUS_ONLINE);

	// Initializing global variables, pt. 2
	nodeinfo_my = &nodeinfo[node_id_my];

	// Running thread, that will process background communicating routines with another nodes.
	// The process is based on function cluster_loop() [let's use shorthand "cluster_loop()-thread"]
	ret = pthread_create(&pthread_cluster, NULL, (void *(*)(void *))cluster_loop, NULL);

	return ret;
}

/**
 * @brief 			(syncop) Sends signal to cluster_loop()-thread
 * 
 * @param[in] 	signal 		Signal number
 *
 * @retval	zero 		Successfully send the signal
 * @retval	non-zero 	Got error, while sending the signal
 * 
 */

static inline int cluster_signal(int signal) {
	if(pthread_cluster)
		return pthread_kill(pthread_cluster, signal);

	return 0;
}


extern int cluster_modtime_exchange_cleanup();
/**
 * @brief 			Antagonist of cluster_init() function. Kills cluster_loop()-thread and cleaning up
 * 
 * @retval	zero 		Successfully initialized
 * @retval	non-zero 	Got error, while initializing
 * 
 */

int cluster_deinit() {
	int ret = 0;

	cluster_signal(SIGTERM);

	ret = pthread_join(pthread_cluster, NULL);

	cluster_io_deinit();

	node_status_change(NODEID_NOID, NODESTATUS_DOESNTEXIST);
#ifdef VERYPARANOID
	int i=0;
#endif
	while(node_count) {
#ifdef VERYPARANOID
		if(i++ > MAXNODES) {
			error("cluster_deinit() looped. Forcing break.");
			break;
		}
#endif
		node_status_change(0, NODESTATUS_DOESNTEXIST);
	}

	close(sock_i);
	close(sock_o);

#ifdef VERYPARANOID
	memset(nodeinfo, 0, sizeof(nodeinfo_t) * NODES_ALLOC);
	nodeinfo_my = NULL;
	node_count  = 0;
	node_online = 0;
	node_id_my  = NODEID_NOID;

	memset(&sa_i,	0, sizeof(sa_i));
	memset(&sa_o,	0, sizeof(sa_o));
#endif

	cluster_modtime_exchange_cleanup();

	return ret;
}


/**
 * @brief 			(syncop) Forces anothes nodes to ignore events about the file or directory
 * 
 * @param[in] 	fpath 		Path to the file or directory
 * 
 * @retval	zero 		Successfully initialized
 * @retval	non-zero 	Got error, while initializing
 * 
 */

int cluster_lock(const char *fpath) {
	return 0;
}


/**
 * @brief 			(syncop) Forces anothes nodes to ignore events about all files and directories listed in queues of "indexes_p"
 * 
 * @retval	zero 		Successfully initialized
 * @retval	non-zero 	Got error, while initializing
 * 
 */

int cluster_lock_byindexes() {
	return 0;
}


/**
 * @brief 			(syncop) Returns events-handling on another nodes about all files and directories, locked by cluster_lock() and cluster_lock_byindexes() from this node
 * 
 * @retval	zero 		Successfully initialized
 * @retval	non-zero 	Got error, while initializing
 * 
 */

int cluster_unlock_all() {
	return 0;
}


#define CLUSTER_LOOP_CHECK(a) {\
	int ret = a;\
	if(ret) {\
		sync_term(ret);\
		return ret;\
	}\
}

/**
 * @brief 			Processes background communicating routines with another nodes. cluster_init() function create a thread for this function.
 * 
 * @retval	zero 		Successfully initialized
 * @retval	non-zero 	Got error, while initializing
 * 
 */

int cluster_loop() {
	int ret = 0;
	sigset_t sigset_cluster;

	// Ignoring SIGINT signal

	sigemptyset(&sigset_cluster);
	sigaddset(&sigset_cluster, SIGINT);
	CLUSTER_LOOP_CHECK(pthread_sigmask(SIG_BLOCK, &sigset_cluster, NULL));

	// Don't ignoring SIGTERM signal

	sigemptyset(&sigset_cluster);
	sigaddset(&sigset_cluster, SIGTERM);
	CLUSTER_LOOP_CHECK(pthread_sigmask(SIG_UNBLOCK, &sigset_cluster, NULL));

	// Starting the loop

	debug(3, "cluster_loop() started.");

	while(1) {
		int _ret;
		// Waiting for event
		fd_set rfds;
		FD_ZERO(&rfds);
		FD_SET(sock_i, &rfds);
		debug(3, "select()");
		_ret = select(sock_i+1, &rfds, NULL, NULL, NULL);

		// Exit if error
		if((_ret == -1) && (errno != EINTR)) {
			ret = errno;
			sync_term(ret);
			break;
		}

		// Breaking the loop, if there's SIGTERM signal for this thread
		debug(3, "sigpending()");
		if(sigpending(&sigset_cluster))
			if(sigismember(&sigset_cluster, SIGTERM))
				break;

		// Processing new messages
		debug(3, "cluster_recv_proc()");
		if((ret=cluster_recv_proc(0))) {
			sync_term(ret);
			break;
		}
	}

	debug(3, "cluster_loop() finished with exitcode %i.", ret);
	return ret;
#ifdef DOXYGEN
	sync_term(0);
#endif
}


/**
 * @brief 			Updating information about modification time of a directory.
 * 
 * @param[in]	path		Canonized path to updated file/dir
 * @param[in]	dirlevel	Directory level provided by fts (man 3 fts)
 * @param[in]	st_mode		st_mode value to detect is it directory or not (S_IFDIR or not)
 * 
 * @retval	zero 		Successfully initialized
 * @retval	non-zero 	Got error, while initializing
 * 
 */

int cluster_modtime_update(const char *path, short int dirlevel, mode_t st_mode) {
	// "modtime" is incorrent name-part of function. Actually it updates "change time" (man 2 lstat64).
	int ret;

	// Getting relative directory level (depth)
	short int dirlevel_rel = dirlevel - ctx_p->watchdir_dirlevel;

	if((st_mode & S_IFMT) == S_IFDIR)
		dirlevel_rel++;

	// Don't remembering information about directories with level beyond the limits
	if((dirlevel_rel > ctx_p->cluster_scan_dl_max) || (dirlevel_rel < ctx_p->cluster_hash_dl_min))
		return 0;


	// Getting directory/file-'s information (including "change time" aka "st_ctime")
	stat64_t stat64;
	ret=lstat64(path, &stat64);
	if(ret) {
		error("Cannot lstat64()", path);
		return errno;
	}

	// Getting absolute directory path
	const char *dirpath;
	if((st_mode & S_IFMT) == S_IFDIR) {
		dirpath = path;
	} else {
		char *path_dup = strdup(path);
		dirpath = (const char *)dirname(path_dup);
		free(path_dup);
	}

	// Getting relative directory path
	//	Initializing
	size_t  dirpath_len   = strlen(dirpath);
	char   *dirpath_rel_p = xmalloc(dirpath_len+1);
	char   *dirpath_rel   = dirpath_rel_p;

	const char *dirpath_rel_full     = &dirpath[ctx_p->watchdirlen];
	size_t      dirpath_rel_full_len = dirpath_len - ctx_p->watchdirlen;

	// 	Getting coodinate of the end (directory path is already canonized, so we can simply count number of slashes to get directory level)
	int     slashcount=0;
	size_t  dirpath_rel_end=0;
	while(dirpath_rel_full[dirpath_rel_end] && (dirpath_rel_end < dirpath_rel_full_len)) {
		if(dirpath_rel_full[dirpath_rel_end] == '/') {
			slashcount++;
			if(slashcount >= ctx_p->cluster_hash_dl_max)
				break;
		}
		dirpath_rel_end++;
	}

	//	Copy the required part of path to dirpath_rel
	memcpy(dirpath_rel, dirpath_rel_full, dirpath_rel_end);

	
	// Updating "st_ctime" information. We should check current value for this directory and update it only if it less or not set.
	//	Checking current value
	char toupdate = 0;
	gpointer ctime_gp = g_hash_table_lookup(nodeinfo_my->modtime_ht, dirpath_rel);
	if(ctime_gp == NULL)
		toupdate++;
	else if(GPOINTER_TO_INT(ctime_gp) < stat64.st_ctime)
		toupdate++;

	//	g_hash_table_replace() will replace existent information about the directory or create it if it doesn't exist.
	if(toupdate)
		g_hash_table_replace(nodeinfo_my->modtime_ht, strdup(dirpath_rel), GINT_TO_POINTER(stat64.st_ctime));

	// Why I'm using "st_ctime" instead of "st_mtime"? Because "st_ctime" also updates on updating inode information.
	
	return 0;
}


/**
 * @brief 			Puts entry to list to be send to other nodes. To be called from cluster_modtime_exchange()
 *
 * @param[in] 	pushrentry_arg_p Pointer to pushentry_arg structure
 * 
 */

void cluster_modtime_exchange_pushentry(gpointer dir_gp, gpointer modtype_gp, void *pushentry_arg_gp) {
	struct pushdoubleentry_arg *pushentry_arg_p = (struct pushdoubleentry_arg *)pushentry_arg_gp;
	char  *dir   = (char *)dir_gp;
	time_t ctime = (time_t)GPOINTER_TO_INT(modtype_gp);
	size_t size  = strlen(dir)+1;				// TODO: strlen should be already prepared
								// but not re-calculated here

	if(pushentry_arg_p->allocated <= pushentry_arg_p->total) {
		pushentry_arg_p->allocated += ALLOC_PORTION;
		pushentry_arg_p->entry      = (struct doubleentry *)
			xrealloc(
				(char *)pushentry_arg_p->entry, 
				pushentry_arg_p->allocated * sizeof(*pushentry_arg_p->entry)
			);
	}

	pushentry_arg_p->entry[pushentry_arg_p->total].dat0  = dir;
	pushentry_arg_p->entry[pushentry_arg_p->total].size0 = size;
	pushentry_arg_p->entry[pushentry_arg_p->total].dat1  = (void *)ctime;	// Will be problems if sizeof(time_t) > sizeof(void *)
	pushentry_arg_p->entry[pushentry_arg_p->total].size1 = sizeof(ctime);

	pushentry_arg_p->size += size;
	pushentry_arg_p->total++;

	return;
}


static struct pushdoubleentry_arg cluster_modtime_exchange_pushentry_arg = {0};
/**
 * @brief 			Clean up after the last run of cluster_modtime_exchange.
 * 
 * @retval	zero 		Successfully initialized
 * @retval	non-zero 	Got error, while initializing
 * 
 */

int cluster_modtime_exchange_cleanup() {
	struct pushdoubleentry_arg *pushentry_arg_p = &cluster_modtime_exchange_pushentry_arg;

	int i=0;
	while(i < pushentry_arg_p->allocated) {
		if(pushentry_arg_p->entry[i].alloc0)
			free(pushentry_arg_p->entry[i].dat0);
		if(pushentry_arg_p->entry[i].alloc1)
			free(pushentry_arg_p->entry[i].dat1);
		i++;
	}

	free(pushentry_arg_p->entry);

#ifdef VERYPARANOID
	memset(pushentry_arg_p, 0, sizeof(*pushentry_arg_p));
#endif

	return 0;
}


/**
 * @brief 			Exchanging with "modtime_ht"-s to be able to compare them.
 * 
 * @retval	zero 		Successfully initialized
 * @retval	non-zero 	Got error, while initializing
 * 
 */

int cluster_modtime_exchange() {
	struct pushdoubleentry_arg *pushentry_arg_p = &cluster_modtime_exchange_pushentry_arg;

	// Getting hash table entries
	pushentry_arg_p->size=0;
	pushentry_arg_p->total=0;
	g_hash_table_foreach(nodeinfo_my->modtime_ht, cluster_modtime_exchange_pushentry, (void *)pushentry_arg_p);

	if(!pushentry_arg_p->total) {
		// !!!
	}

	// Calculating required RAM to compile clustercmd
	size_t toalloc = 0;
	int i = 0;
	while(i < pushentry_arg_p->total) {
		toalloc += 4;					// for size header
		toalloc += pushentry_arg_p->entry[i].size0;	// for path
		toalloc += pushentry_arg_p->entry[i].size1;	// for ctime
	}

	// Allocating space for the clustercmd
	clustercmd_t *clustercmd_p = (clustercmd_t *)xmalloc(sizeof(clustercmdhdr_t) + toalloc);
	memset(clustercmd_p, 0, sizeof(clustercmdhdr_t));

	// Setting up clustercmd
	clustercmd_p->h.dst_node_id	= NODEID_NOID;
	clustercmd_p->h.cmd_id		= CLUSTERCMDID_HT_EXCH;
	clustercmd_p->h.data_len	= toalloc;

	// Filing clustercmd with hash-table entriyes
	i = 0;
	clustercmd_ht_exch_t *clustercmd_ht_exch_p = &clustercmd_p->data.ht_exch;
	while(i < pushentry_arg_p->total) {
		// Setting the data

		clustercmd_ht_exch_p->ctime       = (time_t)pushentry_arg_p->entry[i].dat1;
		clustercmd_ht_exch_p->path_length = (time_t)pushentry_arg_p->entry[i].size0;

		memcpy(
			clustercmd_ht_exch_p->path,
			pushentry_arg_p->entry[i].dat0,
			clustercmd_ht_exch_p->path_length
		);

		// Pointing to space for next entry:
		size_t offset = sizeof(clustercmd_ht_exch_t)-1+pushentry_arg_p->entry[i].size0;

		clustercmd_ht_exch_p = (clustercmd_ht_exch_t *)
			(&((char *) clustercmd_ht_exch_p)[offset] );
	}

	// Sending
	cluster_send(clustercmd_p);

	// Cleanup
	free(clustercmd_p);

	return 0;
}


/**
 * @brief 			(syncop) Syncing file tree with another nodes with using of directories' modification time as a recent-detector.
 * 
 * @param[in] 	dirpath		Path to the directory
 * 
 * @retval	zero 		Successfully initialized
 * @retval	non-zero 	Got error, while initializing
 * 
 */

int cluster_initialsync() {
	cluster_modtime_exchange();

	return 0;
}


/**
 * @brief 			(syncop) "Captures" right to update the file or directory to another nodes. It just removes events about the file of directory from another nodes
 * 
 * @param[in] 	dirpath		Path to the directory
 * 
 * @retval	zero 		Successfully initialized
 * @retval	non-zero 	Got error, while initializing
 * 
 */

int cluster_capture(const char *path) {
	return 0;
}

#endif