net/colo-compare.c

   1 /*
   2  * COarse-grain LOck-stepping Virtual Machines for Non-stop Service (COLO)
   3  * (a.k.a. Fault Tolerance or Continuous Replication)
   4  *
   5  * Copyright (c) 2016 HUAWEI TECHNOLOGIES CO., LTD.
   6  * Copyright (c) 2016 FUJITSU LIMITED
   7  * Copyright (c) 2016 Intel Corporation
   8  *
   9  * Author: Zhang Chen <zhangchen.fnst@cn.fujitsu.com>
  10  *
  11  * This work is licensed under the terms of the GNU GPL, version 2 or
  12  * later.  See the COPYING file in the top-level directory.
  13  */
  14
  15 #include "qemu/osdep.h"
  16 #include "qemu/error-report.h"
  17 #include "trace.h"
  18 #include "qemu-common.h"
  19 #include "qapi/qmp/qerror.h"
  20 #include "qapi/error.h"
  21 #include "net/net.h"
  22 #include "net/eth.h"
  23 #include "qom/object_interfaces.h"
  24 #include "qemu/iov.h"
  25 #include "qom/object.h"
  26 #include "qemu/typedefs.h"
  27 #include "net/queue.h"
  28 #include "sysemu/char.h"
  29 #include "qemu/sockets.h"
  30 #include "qapi-visit.h"
  31 #include "net/colo.h"
  32
  33 #define TYPE_COLO_COMPARE "colo-compare"
  34 #define COLO_COMPARE(obj) \
  35     OBJECT_CHECK(CompareState, (obj), TYPE_COLO_COMPARE)
  36
  37 #define COMPARE_READ_LEN_MAX NET_BUFSIZE
  38 #define MAX_QUEUE_SIZE 1024
  39
  40 /* TODO: Should be configurable */
  41 #define REGULAR_PACKET_CHECK_MS 3000
  42
  43 /*
  44   + CompareState ++
  45   |               |
  46   +---------------+   +---------------+         +---------------+
  47   |conn list      +--->conn           +--------->conn           |
  48   +---------------+   +---------------+         +---------------+
  49   |               |     |           |             |          |
  50   +---------------+ +---v----+  +---v----+    +---v----+ +---v----+
  51                     |primary |  |secondary    |primary | |secondary
  52                     |packet  |  |packet  +    |packet  | |packet  +
  53                     +--------+  +--------+    +--------+ +--------+
  54                         |           |             |          |
  55                     +---v----+  +---v----+    +---v----+ +---v----+
  56                     |primary |  |secondary    |primary | |secondary
  57                     |packet  |  |packet  +    |packet  | |packet  +
  58                     +--------+  +--------+    +--------+ +--------+
  59                         |           |             |          |
  60                     +---v----+  +---v----+    +---v----+ +---v----+
  61                     |primary |  |secondary    |primary | |secondary
  62                     |packet  |  |packet  +    |packet  | |packet  +
  63                     +--------+  +--------+    +--------+ +--------+
  64 */
  65 typedef struct CompareState {
  66     Object parent;
  67
  68     char *pri_indev;
  69     char *sec_indev;
  70     char *outdev;
  71     CharBackend chr_pri_in;
  72     CharBackend chr_sec_in;
  73     CharBackend chr_out;
  74     SocketReadState pri_rs;
  75     SocketReadState sec_rs;
  76
  77     /* connection list: the connections belonged to this NIC could be found
  78      * in this list.
  79      * element type: Connection
  80      */
  81     GQueue conn_list;
  82     /* hashtable to save connection */
  83     GHashTable *connection_track_table;
  84     /* compare thread, a thread for each NIC */
  85     QemuThread thread;
  86     /* Timer used on the primary to find packets that are never matched */
  87     QEMUTimer *timer;
  88     QemuMutex timer_check_lock;
  89 } CompareState;
  90
  91 typedef struct CompareClass {
  92     ObjectClass parent_class;
  93 } CompareClass;
  94
  95 enum {
  96     PRIMARY_IN = 0,
  97     SECONDARY_IN,
  98 };
  99
 100 static int compare_chr_send(CharBackend *out,
 101                             const uint8_t *buf,
 102                             uint32_t size);
 103
 104 static gint seq_sorter(Packet *a, Packet *b, gpointer data)
 105 {
 106     struct tcphdr *atcp, *btcp;
 107
 108     atcp = (struct tcphdr *)(a->transport_header);
 109     btcp = (struct tcphdr *)(b->transport_header);
 110     return ntohl(atcp->th_seq) - ntohl(btcp->th_seq);
 111 }
 112
 113 /*
 114  * Return 0 on success, if return -1 means the pkt
 115  * is unsupported(arp and ipv6) and will be sent later
 116  */
 117 static int packet_enqueue(CompareState *s, int mode)
 118 {
 119     ConnectionKey key;
 120     Packet *pkt = NULL;
 121     Connection *conn;
 122
 123     if (mode == PRIMARY_IN) {
 124         pkt = packet_new(s->pri_rs.buf, s->pri_rs.packet_len);
 125     } else {
 126         pkt = packet_new(s->sec_rs.buf, s->sec_rs.packet_len);
 127     }
 128
 129     if (parse_packet_early(pkt)) {
 130         packet_destroy(pkt, NULL);
 131         pkt = NULL;
 132         return -1;
 133     }
 134     fill_connection_key(pkt, &key);
 135
 136     conn = connection_get(s->connection_track_table,
 137                           &key,
 138                           &s->conn_list);
 139
 140     if (!conn->processing) {
 141         g_queue_push_tail(&s->conn_list, conn);
 142         conn->processing = true;
 143     }
 144
 145     if (mode == PRIMARY_IN) {
 146         if (g_queue_get_length(&conn->primary_list) <=
 147                                MAX_QUEUE_SIZE) {
 148             g_queue_push_tail(&conn->primary_list, pkt);
 149             if (conn->ip_proto == IPPROTO_TCP) {
 150                 g_queue_sort(&conn->primary_list,
 151                              (GCompareDataFunc)seq_sorter,
 152                              NULL);
 153             }
 154         } else {
 155             error_report("colo compare primary queue size too big,"
 156                          "drop packet");
 157         }
 158     } else {
 159         if (g_queue_get_length(&conn->secondary_list) <=
 160                                MAX_QUEUE_SIZE) {
 161             g_queue_push_tail(&conn->secondary_list, pkt);
 162             if (conn->ip_proto == IPPROTO_TCP) {
 163                 g_queue_sort(&conn->secondary_list,
 164                              (GCompareDataFunc)seq_sorter,
 165                              NULL);
 166             }
 167         } else {
 168             error_report("colo compare secondary queue size too big,"
 169                          "drop packet");
 170         }
 171     }
 172
 173     return 0;
 174 }
 175
 176 /*
 177  * The IP packets sent by primary and secondary
 178  * will be compared in here
 179  * TODO support ip fragment, Out-Of-Order
 180  * return:    0  means packet same
 181  *            > 0 || < 0 means packet different
 182  */
 183 static int colo_packet_compare(Packet *ppkt, Packet *spkt)
 184 {
 185     trace_colo_compare_ip_info(ppkt->size, inet_ntoa(ppkt->ip->ip_src),
 186                                inet_ntoa(ppkt->ip->ip_dst), spkt->size,
 187                                inet_ntoa(spkt->ip->ip_src),
 188                                inet_ntoa(spkt->ip->ip_dst));
 189
 190     if (ppkt->size == spkt->size) {
 191         return memcmp(ppkt->data, spkt->data, spkt->size);
 192     } else {
 193         return -1;
 194     }
 195 }
 196
 197 /*
 198  * Called from the compare thread on the primary
 199  * for compare tcp packet
 200  * compare_tcp copied from Dr. David Alan Gilbert's branch
 201  */
 202 static int colo_packet_compare_tcp(Packet *spkt, Packet *ppkt)
 203 {
 204     struct tcphdr *ptcp, *stcp;
 205     int res;
 206
 207     trace_colo_compare_main("compare tcp");
 208     if (ppkt->size != spkt->size) {
 209         if (trace_event_get_state(TRACE_COLO_COMPARE_MISCOMPARE)) {
 210             trace_colo_compare_main("pkt size not same");
 211         }
 212         return -1;
 213     }
 214
 215     ptcp = (struct tcphdr *)ppkt->transport_header;
 216     stcp = (struct tcphdr *)spkt->transport_header;
 217
 218     /*
 219      * The 'identification' field in the IP header is *very* random
 220      * it almost never matches.  Fudge this by ignoring differences in
 221      * unfragmented packets; they'll normally sort themselves out if different
 222      * anyway, and it should recover at the TCP level.
 223      * An alternative would be to get both the primary and secondary to rewrite
 224      * somehow; but that would need some sync traffic to sync the state
 225      */
 226     if (ntohs(ppkt->ip->ip_off) & IP_DF) {
 227         spkt->ip->ip_id = ppkt->ip->ip_id;
 228         /* and the sum will be different if the IDs were different */
 229         spkt->ip->ip_sum = ppkt->ip->ip_sum;
 230     }
 231
 232     res = memcmp(ppkt->data + ETH_HLEN, spkt->data + ETH_HLEN,
 233                 (spkt->size - ETH_HLEN));
 234
 235     if (res != 0 && trace_event_get_state(TRACE_COLO_COMPARE_MISCOMPARE)) {
 236         trace_colo_compare_pkt_info_src(inet_ntoa(ppkt->ip->ip_src),
 237                                         ntohl(stcp->th_seq),
 238                                         ntohl(stcp->th_ack),
 239                                         res, stcp->th_flags,
 240                                         spkt->size);
 241
 242         trace_colo_compare_pkt_info_dst(inet_ntoa(ppkt->ip->ip_dst),
 243                                         ntohl(ptcp->th_seq),
 244                                         ntohl(ptcp->th_ack),
 245                                         res, ptcp->th_flags,
 246                                         ppkt->size);
 247
 248         qemu_hexdump((char *)ppkt->data, stderr,
 249                      "colo-compare ppkt", ppkt->size);
 250         qemu_hexdump((char *)spkt->data, stderr,
 251                      "colo-compare spkt", spkt->size);
 252     }
 253
 254     return res;
 255 }
 256
 257 /*
 258  * Called from the compare thread on the primary
 259  * for compare udp packet
 260  */
 261 static int colo_packet_compare_udp(Packet *spkt, Packet *ppkt)
 262 {
 263     int ret;
 264
 265     trace_colo_compare_main("compare udp");
 266     ret = colo_packet_compare(ppkt, spkt);
 267
 268     if (ret) {
 269         trace_colo_compare_udp_miscompare("primary pkt size", ppkt->size);
 270         qemu_hexdump((char *)ppkt->data, stderr, "colo-compare", ppkt->size);
 271         trace_colo_compare_udp_miscompare("Secondary pkt size", spkt->size);
 272         qemu_hexdump((char *)spkt->data, stderr, "colo-compare", spkt->size);
 273     }
 274
 275     return ret;
 276 }
 277
 278 /*
 279  * Called from the compare thread on the primary
 280  * for compare icmp packet
 281  */
 282 static int colo_packet_compare_icmp(Packet *spkt, Packet *ppkt)
 283 {
 284     int network_length;
 285
 286     trace_colo_compare_main("compare icmp");
 287     network_length = ppkt->ip->ip_hl * 4;
 288     if (ppkt->size != spkt->size ||
 289         ppkt->size < network_length + ETH_HLEN) {
 290         return -1;
 291     }
 292
 293     if (colo_packet_compare(ppkt, spkt)) {
 294         trace_colo_compare_icmp_miscompare("primary pkt size",
 295                                            ppkt->size);
 296         qemu_hexdump((char *)ppkt->data, stderr, "colo-compare",
 297                      ppkt->size);
 298         trace_colo_compare_icmp_miscompare("Secondary pkt size",
 299                                            spkt->size);
 300         qemu_hexdump((char *)spkt->data, stderr, "colo-compare",
 301                      spkt->size);
 302         return -1;
 303     } else {
 304         return 0;
 305     }
 306 }
 307
 308 /*
 309  * Called from the compare thread on the primary
 310  * for compare other packet
 311  */
 312 static int colo_packet_compare_other(Packet *spkt, Packet *ppkt)
 313 {
 314     trace_colo_compare_main("compare other");
 315     trace_colo_compare_ip_info(ppkt->size, inet_ntoa(ppkt->ip->ip_src),
 316                                inet_ntoa(ppkt->ip->ip_dst), spkt->size,
 317                                inet_ntoa(spkt->ip->ip_src),
 318                                inet_ntoa(spkt->ip->ip_dst));
 319     return colo_packet_compare(ppkt, spkt);
 320 }
 321
 322 static int colo_old_packet_check_one(Packet *pkt, int64_t *check_time)
 323 {
 324     int64_t now = qemu_clock_get_ms(QEMU_CLOCK_HOST);
 325
 326     if ((now - pkt->creation_ms) > (*check_time)) {
 327         trace_colo_old_packet_check_found(pkt->creation_ms);
 328         return 0;
 329     } else {
 330         return 1;
 331     }
 332 }
 333
 334 static void colo_old_packet_check_one_conn(void *opaque,
 335                                            void *user_data)
 336 {
 337     Connection *conn = opaque;
 338     GList *result = NULL;
 339     int64_t check_time = REGULAR_PACKET_CHECK_MS;
 340
 341     result = g_queue_find_custom(&conn->primary_list,
 342                                  &check_time,
 343                                  (GCompareFunc)colo_old_packet_check_one);
 344
 345     if (result) {
 346         /* do checkpoint will flush old packet */
 347         /* TODO: colo_notify_checkpoint();*/
 348     }
 349 }
 350
 351 /*
 352  * Look for old packets that the secondary hasn't matched,
 353  * if we have some then we have to checkpoint to wake
 354  * the secondary up.
 355  */
 356 static void colo_old_packet_check(void *opaque)
 357 {
 358     CompareState *s = opaque;
 359
 360     g_queue_foreach(&s->conn_list, colo_old_packet_check_one_conn, NULL);
 361 }
 362
 363 /*
 364  * Called from the compare thread on the primary
 365  * for compare connection
 366  */
 367 static void colo_compare_connection(void *opaque, void *user_data)
 368 {
 369     CompareState *s = user_data;
 370     Connection *conn = opaque;
 371     Packet *pkt = NULL;
 372     GList *result = NULL;
 373     int ret;
 374
 375     while (!g_queue_is_empty(&conn->primary_list) &&
 376            !g_queue_is_empty(&conn->secondary_list)) {
 377         qemu_mutex_lock(&s->timer_check_lock);
 378         pkt = g_queue_pop_tail(&conn->primary_list);
 379         qemu_mutex_unlock(&s->timer_check_lock);
 380         switch (conn->ip_proto) {
 381         case IPPROTO_TCP:
 382             result = g_queue_find_custom(&conn->secondary_list,
 383                      pkt, (GCompareFunc)colo_packet_compare_tcp);
 384             break;
 385         case IPPROTO_UDP:
 386             result = g_queue_find_custom(&conn->secondary_list,
 387                      pkt, (GCompareFunc)colo_packet_compare_udp);
 388             break;
 389         case IPPROTO_ICMP:
 390             result = g_queue_find_custom(&conn->secondary_list,
 391                      pkt, (GCompareFunc)colo_packet_compare_icmp);
 392             break;
 393         default:
 394             result = g_queue_find_custom(&conn->secondary_list,
 395                      pkt, (GCompareFunc)colo_packet_compare_other);
 396             break;
 397         }
 398
 399         if (result) {
 400             ret = compare_chr_send(&s->chr_out, pkt->data, pkt->size);
 401             if (ret < 0) {
 402                 error_report("colo_send_primary_packet failed");
 403             }
 404             trace_colo_compare_main("packet same and release packet");
 405             g_queue_remove(&conn->secondary_list, result->data);
 406             packet_destroy(pkt, NULL);
 407         } else {
 408             /*
 409              * If one packet arrive late, the secondary_list or
 410              * primary_list will be empty, so we can't compare it
 411              * until next comparison.
 412              */
 413             trace_colo_compare_main("packet different");
 414             qemu_mutex_lock(&s->timer_check_lock);
 415             g_queue_push_tail(&conn->primary_list, pkt);
 416             qemu_mutex_unlock(&s->timer_check_lock);
 417             /* TODO: colo_notify_checkpoint();*/
 418             break;
 419         }
 420     }
 421 }
 422
 423 static int compare_chr_send(CharBackend *out,
 424                             const uint8_t *buf,
 425                             uint32_t size)
 426 {
 427     int ret = 0;
 428     uint32_t len = htonl(size);
 429
 430     if (!size) {
 431         return 0;
 432     }
 433
 434     ret = qemu_chr_fe_write_all(out, (uint8_t *)&len, sizeof(len));
 435     if (ret != sizeof(len)) {
 436         goto err;
 437     }
 438
 439     ret = qemu_chr_fe_write_all(out, (uint8_t *)buf, size);
 440     if (ret != size) {
 441         goto err;
 442     }
 443
 444     return 0;
 445
 446 err:
 447     return ret < 0 ? ret : -EIO;
 448 }
 449
 450 static int compare_chr_can_read(void *opaque)
 451 {
 452     return COMPARE_READ_LEN_MAX;
 453 }
 454
 455 /*
 456  * Called from the main thread on the primary for packets
 457  * arriving over the socket from the primary.
 458  */
 459 static void compare_pri_chr_in(void *opaque, const uint8_t *buf, int size)
 460 {
 461     CompareState *s = COLO_COMPARE(opaque);
 462     int ret;
 463
 464     ret = net_fill_rstate(&s->pri_rs, buf, size);
 465     if (ret == -1) {
 466         qemu_chr_fe_set_handlers(&s->chr_pri_in, NULL, NULL, NULL,
 467                                  NULL, NULL, true);
 468         error_report("colo-compare primary_in error");
 469     }
 470 }
 471
 472 /*
 473  * Called from the main thread on the primary for packets
 474  * arriving over the socket from the secondary.
 475  */
 476 static void compare_sec_chr_in(void *opaque, const uint8_t *buf, int size)
 477 {
 478     CompareState *s = COLO_COMPARE(opaque);
 479     int ret;
 480
 481     ret = net_fill_rstate(&s->sec_rs, buf, size);
 482     if (ret == -1) {
 483         qemu_chr_fe_set_handlers(&s->chr_sec_in, NULL, NULL, NULL,
 484                                  NULL, NULL, true);
 485         error_report("colo-compare secondary_in error");
 486     }
 487 }
 488
 489 static void *colo_compare_thread(void *opaque)
 490 {
 491     GMainContext *worker_context;
 492     GMainLoop *compare_loop;
 493     CompareState *s = opaque;
 494
 495     worker_context = g_main_context_new();
 496
 497     qemu_chr_fe_set_handlers(&s->chr_pri_in, compare_chr_can_read,
 498                              compare_pri_chr_in, NULL, s, worker_context, true);
 499     qemu_chr_fe_set_handlers(&s->chr_sec_in, compare_chr_can_read,
 500                              compare_sec_chr_in, NULL, s, worker_context, true);
 501
 502     compare_loop = g_main_loop_new(worker_context, FALSE);
 503
 504     g_main_loop_run(compare_loop);
 505
 506     g_main_loop_unref(compare_loop);
 507     g_main_context_unref(worker_context);
 508     return NULL;
 509 }
 510
 511 static char *compare_get_pri_indev(Object *obj, Error **errp)
 512 {
 513     CompareState *s = COLO_COMPARE(obj);
 514
 515     return g_strdup(s->pri_indev);
 516 }
 517
 518 static void compare_set_pri_indev(Object *obj, const char *value, Error **errp)
 519 {
 520     CompareState *s = COLO_COMPARE(obj);
 521
 522     g_free(s->pri_indev);
 523     s->pri_indev = g_strdup(value);
 524 }
 525
 526 static char *compare_get_sec_indev(Object *obj, Error **errp)
 527 {
 528     CompareState *s = COLO_COMPARE(obj);
 529
 530     return g_strdup(s->sec_indev);
 531 }
 532
 533 static void compare_set_sec_indev(Object *obj, const char *value, Error **errp)
 534 {
 535     CompareState *s = COLO_COMPARE(obj);
 536
 537     g_free(s->sec_indev);
 538     s->sec_indev = g_strdup(value);
 539 }
 540
 541 static char *compare_get_outdev(Object *obj, Error **errp)
 542 {
 543     CompareState *s = COLO_COMPARE(obj);
 544
 545     return g_strdup(s->outdev);
 546 }
 547
 548 static void compare_set_outdev(Object *obj, const char *value, Error **errp)
 549 {
 550     CompareState *s = COLO_COMPARE(obj);
 551
 552     g_free(s->outdev);
 553     s->outdev = g_strdup(value);
 554 }
 555
 556 static void compare_pri_rs_finalize(SocketReadState *pri_rs)
 557 {
 558     CompareState *s = container_of(pri_rs, CompareState, pri_rs);
 559
 560     if (packet_enqueue(s, PRIMARY_IN)) {
 561         trace_colo_compare_main("primary: unsupported packet in");
 562         compare_chr_send(&s->chr_out, pri_rs->buf, pri_rs->packet_len);
 563     } else {
 564         /* compare connection */
 565         g_queue_foreach(&s->conn_list, colo_compare_connection, s);
 566     }
 567 }
 568
 569 static void compare_sec_rs_finalize(SocketReadState *sec_rs)
 570 {
 571     CompareState *s = container_of(sec_rs, CompareState, sec_rs);
 572
 573     if (packet_enqueue(s, SECONDARY_IN)) {
 574         trace_colo_compare_main("secondary: unsupported packet in");
 575     } else {
 576         /* compare connection */
 577         g_queue_foreach(&s->conn_list, colo_compare_connection, s);
 578     }
 579 }
 580
 581
 582 /*
 583  * Return 0 is success.
 584  * Return 1 is failed.
 585  */
 586 static int find_and_check_chardev(Chardev **chr,
 587                                   char *chr_name,
 588                                   Error **errp)
 589 {
 590     *chr = qemu_chr_find(chr_name);
 591     if (*chr == NULL) {
 592         error_setg(errp, "Device '%s' not found",
 593                    chr_name);
 594         return 1;
 595     }
 596
 597     if (!qemu_chr_has_feature(*chr, QEMU_CHAR_FEATURE_RECONNECTABLE)) {
 598         error_setg(errp, "chardev \"%s\" is not reconnectable",
 599                    chr_name);
 600         return 1;
 601     }
 602
 603     return 0;
 604 }
 605
 606 /*
 607  * Check old packet regularly so it can watch for any packets
 608  * that the secondary hasn't produced equivalents of.
 609  */
 610 static void check_old_packet_regular(void *opaque)
 611 {
 612     CompareState *s = opaque;
 613
 614     timer_mod(s->timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) +
 615               REGULAR_PACKET_CHECK_MS);
 616     /* if have old packet we will notify checkpoint */
 617     /*
 618      * TODO: Make timer handler run in compare thread
 619      * like qemu_chr_add_handlers_full.
 620      */
 621     qemu_mutex_lock(&s->timer_check_lock);
 622     colo_old_packet_check(s);
 623     qemu_mutex_unlock(&s->timer_check_lock);
 624 }
 625
 626 /*
 627  * Called from the main thread on the primary
 628  * to setup colo-compare.
 629  */
 630 static void colo_compare_complete(UserCreatable *uc, Error **errp)
 631 {
 632     CompareState *s = COLO_COMPARE(uc);
 633     Chardev *chr;
 634     char thread_name[64];
 635     static int compare_id;
 636
 637     if (!s->pri_indev || !s->sec_indev || !s->outdev) {
 638         error_setg(errp, "colo compare needs 'primary_in' ,"
 639                    "'secondary_in','outdev' property set");
 640         return;
 641     } else if (!strcmp(s->pri_indev, s->outdev) ||
 642                !strcmp(s->sec_indev, s->outdev) ||
 643                !strcmp(s->pri_indev, s->sec_indev)) {
 644         error_setg(errp, "'indev' and 'outdev' could not be same "
 645                    "for compare module");
 646         return;
 647     }
 648
 649     if (find_and_check_chardev(&chr, s->pri_indev, errp) ||
 650         !qemu_chr_fe_init(&s->chr_pri_in, chr, errp)) {
 651         return;
 652     }
 653
 654     if (find_and_check_chardev(&chr, s->sec_indev, errp) ||
 655         !qemu_chr_fe_init(&s->chr_sec_in, chr, errp)) {
 656         return;
 657     }
 658
 659     if (find_and_check_chardev(&chr, s->outdev, errp) ||
 660         !qemu_chr_fe_init(&s->chr_out, chr, errp)) {
 661         return;
 662     }
 663
 664     net_socket_rs_init(&s->pri_rs, compare_pri_rs_finalize);
 665     net_socket_rs_init(&s->sec_rs, compare_sec_rs_finalize);
 666
 667     g_queue_init(&s->conn_list);
 668     qemu_mutex_init(&s->timer_check_lock);
 669
 670     s->connection_track_table = g_hash_table_new_full(connection_key_hash,
 671                                                       connection_key_equal,
 672                                                       g_free,
 673                                                       connection_destroy);
 674
 675     sprintf(thread_name, "colo-compare %d", compare_id);
 676     qemu_thread_create(&s->thread, thread_name,
 677                        colo_compare_thread, s,
 678                        QEMU_THREAD_JOINABLE);
 679     compare_id++;
 680
 681     /* A regular timer to kick any packets that the secondary doesn't match */
 682     s->timer = timer_new_ms(QEMU_CLOCK_VIRTUAL, /* Only when guest runs */
 683                             check_old_packet_regular, s);
 684     timer_mod(s->timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) +
 685                         REGULAR_PACKET_CHECK_MS);
 686
 687     return;
 688 }
 689
 690 static void colo_compare_class_init(ObjectClass *oc, void *data)
 691 {
 692     UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
 693
 694     ucc->complete = colo_compare_complete;
 695 }
 696
 697 static void colo_compare_init(Object *obj)
 698 {
 699     object_property_add_str(obj, "primary_in",
 700                             compare_get_pri_indev, compare_set_pri_indev,
 701                             NULL);
 702     object_property_add_str(obj, "secondary_in",
 703                             compare_get_sec_indev, compare_set_sec_indev,
 704                             NULL);
 705     object_property_add_str(obj, "outdev",
 706                             compare_get_outdev, compare_set_outdev,
 707                             NULL);
 708 }
 709
 710 static void colo_compare_finalize(Object *obj)
 711 {
 712     CompareState *s = COLO_COMPARE(obj);
 713
 714     qemu_chr_fe_deinit(&s->chr_pri_in);
 715     qemu_chr_fe_deinit(&s->chr_sec_in);
 716     qemu_chr_fe_deinit(&s->chr_out);
 717
 718     g_queue_free(&s->conn_list);
 719
 720     if (qemu_thread_is_self(&s->thread)) {
 721         /* compare connection */
 722         g_queue_foreach(&s->conn_list, colo_compare_connection, s);
 723         qemu_thread_join(&s->thread);
 724     }
 725
 726     if (s->timer) {
 727         timer_del(s->timer);
 728     }
 729
 730     qemu_mutex_destroy(&s->timer_check_lock);
 731
 732     g_free(s->pri_indev);
 733     g_free(s->sec_indev);
 734     g_free(s->outdev);
 735 }
 736
 737 static const TypeInfo colo_compare_info = {
 738     .name = TYPE_COLO_COMPARE,
 739     .parent = TYPE_OBJECT,
 740     .instance_size = sizeof(CompareState),
 741     .instance_init = colo_compare_init,
 742     .instance_finalize = colo_compare_finalize,
 743     .class_size = sizeof(CompareClass),
 744     .class_init = colo_compare_class_init,
 745     .interfaces = (InterfaceInfo[]) {
 746         { TYPE_USER_CREATABLE },
 747         { }
 748     }
 749 };
 750
 751 static void register_types(void)
 752 {
 753     type_register_static(&colo_compare_info);
 754 }
 755
 756 type_init(register_types);