aboutsummaryrefslogtreecommitdiff
path: root/net/colo-compare.c
blob: 7489840bde201089cd13e238fa929aa09a2d3864 (plain)
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
/*
 * COarse-grain LOck-stepping Virtual Machines for Non-stop Service (COLO)
 * (a.k.a. Fault Tolerance or Continuous Replication)
 *
 * Copyright (c) 2016 HUAWEI TECHNOLOGIES CO., LTD.
 * Copyright (c) 2016 FUJITSU LIMITED
 * Copyright (c) 2016 Intel Corporation
 *
 * Author: Zhang Chen <zhangchen.fnst@cn.fujitsu.com>
 *
 * This work is licensed under the terms of the GNU GPL, version 2 or
 * later.  See the COPYING file in the top-level directory.
 */

#include "qemu/osdep.h"
#include "qemu-common.h"
#include "qemu/error-report.h"
#include "trace.h"
#include "qapi/error.h"
#include "net/net.h"
#include "net/eth.h"
#include "qom/object_interfaces.h"
#include "qemu/iov.h"
#include "qom/object.h"
#include "net/queue.h"
#include "chardev/char-fe.h"
#include "qemu/sockets.h"
#include "colo.h"
#include "sysemu/iothread.h"
#include "net/colo-compare.h"
#include "migration/colo.h"
#include "migration/migration.h"
#include "util.h"

#define TYPE_COLO_COMPARE "colo-compare"
#define COLO_COMPARE(obj) \
    OBJECT_CHECK(CompareState, (obj), TYPE_COLO_COMPARE)

static QTAILQ_HEAD(, CompareState) net_compares =
       QTAILQ_HEAD_INITIALIZER(net_compares);

static NotifierList colo_compare_notifiers =
    NOTIFIER_LIST_INITIALIZER(colo_compare_notifiers);

#define COMPARE_READ_LEN_MAX NET_BUFSIZE
#define MAX_QUEUE_SIZE 1024

#define COLO_COMPARE_FREE_PRIMARY     0x01
#define COLO_COMPARE_FREE_SECONDARY   0x02

/* TODO: Should be configurable */
#define REGULAR_PACKET_CHECK_MS 3000

static QemuMutex event_mtx;
static QemuCond event_complete_cond;
static int event_unhandled_count;

/*
 *  + CompareState ++
 *  |               |
 *  +---------------+   +---------------+         +---------------+
 *  |   conn list   + - >      conn     + ------- >      conn     + -- > ......
 *  +---------------+   +---------------+         +---------------+
 *  |               |     |           |             |          |
 *  +---------------+ +---v----+  +---v----+    +---v----+ +---v----+
 *                    |primary |  |secondary    |primary | |secondary
 *                    |packet  |  |packet  +    |packet  | |packet  +
 *                    +--------+  +--------+    +--------+ +--------+
 *                        |           |             |          |
 *                    +---v----+  +---v----+    +---v----+ +---v----+
 *                    |primary |  |secondary    |primary | |secondary
 *                    |packet  |  |packet  +    |packet  | |packet  +
 *                    +--------+  +--------+    +--------+ +--------+
 *                        |           |             |          |
 *                    +---v----+  +---v----+    +---v----+ +---v----+
 *                    |primary |  |secondary    |primary | |secondary
 *                    |packet  |  |packet  +    |packet  | |packet  +
 *                    +--------+  +--------+    +--------+ +--------+
 */
typedef struct CompareState {
    Object parent;

    char *pri_indev;
    char *sec_indev;
    char *outdev;
    char *notify_dev;
    CharBackend chr_pri_in;
    CharBackend chr_sec_in;
    CharBackend chr_out;
    CharBackend chr_notify_dev;
    SocketReadState pri_rs;
    SocketReadState sec_rs;
    SocketReadState notify_rs;
    bool vnet_hdr;

    /*
     * Record the connection that through the NIC
     * Element type: Connection
     */
    GQueue conn_list;
    /* Record the connection without repetition */
    GHashTable *connection_track_table;

    IOThread *iothread;
    GMainContext *worker_context;
    QEMUTimer *packet_check_timer;

    QEMUBH *event_bh;
    enum colo_event event;

    QTAILQ_ENTRY(CompareState) next;
} CompareState;

typedef struct CompareClass {
    ObjectClass parent_class;
} CompareClass;

enum {
    PRIMARY_IN = 0,
    SECONDARY_IN,
};


static int compare_chr_send(CompareState *s,
                            const uint8_t *buf,
                            uint32_t size,
                            uint32_t vnet_hdr_len,
                            bool notify_remote_frame);

static bool packet_matches_str(const char *str,
                               const uint8_t *buf,
                               uint32_t packet_len)
{
    if (packet_len != strlen(str)) {
        return false;
    }

    return !memcmp(str, buf, strlen(str));
}

static void notify_remote_frame(CompareState *s)
{
    char msg[] = "DO_CHECKPOINT";
    int ret = 0;

    ret = compare_chr_send(s, (uint8_t *)msg, strlen(msg), 0, true);
    if (ret < 0) {
        error_report("Notify Xen COLO-frame failed");
    }
}

static void colo_compare_inconsistency_notify(CompareState *s)
{
    if (s->notify_dev) {
        notify_remote_frame(s);
    } else {
        notifier_list_notify(&colo_compare_notifiers,
                             migrate_get_current());
    }
}

static gint seq_sorter(Packet *a, Packet *b, gpointer data)
{
    struct tcp_hdr *atcp, *btcp;

    atcp = (struct tcp_hdr *)(a->transport_header);
    btcp = (struct tcp_hdr *)(b->transport_header);
    return ntohl(atcp->th_seq) - ntohl(btcp->th_seq);
}

static void fill_pkt_tcp_info(void *data, uint32_t *max_ack)
{
    Packet *pkt = data;
    struct tcp_hdr *tcphd;

    tcphd = (struct tcp_hdr *)pkt->transport_header;

    pkt->tcp_seq = ntohl(tcphd->th_seq);
    pkt->tcp_ack = ntohl(tcphd->th_ack);
    *max_ack = *max_ack > pkt->tcp_ack ? *max_ack : pkt->tcp_ack;
    pkt->header_size = pkt->transport_header - (uint8_t *)pkt->data
                       + (tcphd->th_off << 2) - pkt->vnet_hdr_len;
    pkt->payload_size = pkt->size - pkt->header_size;
    pkt->seq_end = pkt->tcp_seq + pkt->payload_size;
    pkt->flags = tcphd->th_flags;
}

/*
 * Return 1 on success, if return 0 means the
 * packet will be dropped
 */
static int colo_insert_packet(GQueue *queue, Packet *pkt, uint32_t *max_ack)
{
    if (g_queue_get_length(queue) <= MAX_QUEUE_SIZE) {
        if (pkt->ip->ip_p == IPPROTO_TCP) {
            fill_pkt_tcp_info(pkt, max_ack);
            g_queue_insert_sorted(queue,
                                  pkt,
                                  (GCompareDataFunc)seq_sorter,
                                  NULL);
        } else {
            g_queue_push_tail(queue, pkt);
        }
        return 1;
    }
    return 0;
}

/*
 * Return 0 on success, if return -1 means the pkt
 * is unsupported(arp and ipv6) and will be sent later
 */
static int packet_enqueue(CompareState *s, int mode, Connection **con)
{
    ConnectionKey key;
    Packet *pkt = NULL;
    Connection *conn;

    if (mode == PRIMARY_IN) {
        pkt = packet_new(s->pri_rs.buf,
                         s->pri_rs.packet_len,
                         s->pri_rs.vnet_hdr_len);
    } else {
        pkt = packet_new(s->sec_rs.buf,
                         s->sec_rs.packet_len,
                         s->sec_rs.vnet_hdr_len);
    }

    if (parse_packet_early(pkt)) {
        packet_destroy(pkt, NULL);
        pkt = NULL;
        return -1;
    }
    fill_connection_key(pkt, &key);

    conn = connection_get(s->connection_track_table,
                          &key,
                          &s->conn_list);

    if (!conn->processing) {
        g_queue_push_tail(&s->conn_list, conn);
        conn->processing = true;
    }

    if (mode == PRIMARY_IN) {
        if (!colo_insert_packet(&conn->primary_list, pkt, &conn->pack)) {
            error_report("colo compare primary queue size too big,"
                         "drop packet");
        }
    } else {
        if (!colo_insert_packet(&conn->secondary_list, pkt, &conn->sack)) {
            error_report("colo compare secondary queue size too big,"
                         "drop packet");
        }
    }
    *con = conn;

    return 0;
}

static inline bool after(uint32_t seq1, uint32_t seq2)
{
        return (int32_t)(seq1 - seq2) > 0;
}

static void colo_release_primary_pkt(CompareState *s, Packet *pkt)
{
    int ret;
    ret = compare_chr_send(s,
                           pkt->data,
                           pkt->size,
                           pkt->vnet_hdr_len,
                           false);
    if (ret < 0) {
        error_report("colo send primary packet failed");
    }
    trace_colo_compare_main("packet same and release packet");
    packet_destroy(pkt, NULL);
}

/*
 * The IP packets sent by primary and secondary
 * will be compared in here
 * TODO support ip fragment, Out-Of-Order
 * return:    0  means packet same
 *            > 0 || < 0 means packet different
 */
static int colo_compare_packet_payload(Packet *ppkt,
                                       Packet *spkt,
                                       uint16_t poffset,
                                       uint16_t soffset,
                                       uint16_t len)

{
    if (trace_event_get_state_backends(TRACE_COLO_COMPARE_MISCOMPARE)) {
        char pri_ip_src[20], pri_ip_dst[20], sec_ip_src[20], sec_ip_dst[20];

        strcpy(pri_ip_src, inet_ntoa(ppkt->ip->ip_src));
        strcpy(pri_ip_dst, inet_ntoa(ppkt->ip->ip_dst));
        strcpy(sec_ip_src, inet_ntoa(spkt->ip->ip_src));
        strcpy(sec_ip_dst, inet_ntoa(spkt->ip->ip_dst));

        trace_colo_compare_ip_info(ppkt->size, pri_ip_src,
                                   pri_ip_dst, spkt->size,
                                   sec_ip_src, sec_ip_dst);
    }

    return memcmp(ppkt->data + poffset, spkt->data + soffset, len);
}

/*
 * return true means that the payload is consist and
 * need to make the next comparison, false means do
 * the checkpoint
*/
static bool colo_mark_tcp_pkt(Packet *ppkt, Packet *spkt,
                              int8_t *mark, uint32_t max_ack)
{
    *mark = 0;

    if (ppkt->tcp_seq == spkt->tcp_seq && ppkt->seq_end == spkt->seq_end) {
        if (colo_compare_packet_payload(ppkt, spkt,
                                        ppkt->header_size, spkt->header_size,
                                        ppkt->payload_size)) {
            *mark = COLO_COMPARE_FREE_SECONDARY | COLO_COMPARE_FREE_PRIMARY;
            return true;
        }
    }

    /* one part of secondary packet payload still need to be compared */
    if (!after(ppkt->seq_end, spkt->seq_end)) {
        if (colo_compare_packet_payload(ppkt, spkt,
                                        ppkt->header_size + ppkt->offset,
                                        spkt->header_size + spkt->offset,
                                        ppkt->payload_size - ppkt->offset)) {
            if (!after(ppkt->tcp_ack, max_ack)) {
                *mark = COLO_COMPARE_FREE_PRIMARY;
                spkt->offset += ppkt->payload_size - ppkt->offset;
                return true;
            } else {
                /* secondary guest hasn't ack the data, don't send
                 * out this packet
                 */
                return false;
            }
        }
    } else {
        /* primary packet is longer than secondary packet, compare
         * the same part and mark the primary packet offset
         */
        if (colo_compare_packet_payload(ppkt, spkt,
                                        ppkt->header_size + ppkt->offset,
                                        spkt->header_size + spkt->offset,
                                        spkt->payload_size - spkt->offset)) {
            *mark = COLO_COMPARE_FREE_SECONDARY;
            ppkt->offset += spkt->payload_size - spkt->offset;
            return true;
        }
    }

    return false;
}

static void colo_compare_tcp(CompareState *s, Connection *conn)
{
    Packet *ppkt = NULL, *spkt = NULL;
    int8_t mark;

    /*
     * If ppkt and spkt have the same payload, but ppkt's ACK
     * is greater than spkt's ACK, in this case we can not
     * send the ppkt because it will cause the secondary guest
     * to miss sending some data in the next. Therefore, we
     * record the maximum ACK in the current queue at both
     * primary side and secondary side. Only when the ack is
     * less than the smaller of the two maximum ack, then we
     * can ensure that the packet's payload is acknowledged by
     * primary and secondary.
    */
    uint32_t min_ack = conn->pack > conn->sack ? conn->sack : conn->pack;

pri:
    if (g_queue_is_empty(&conn->primary_list)) {
        return;
    }
    ppkt = g_queue_pop_head(&conn->primary_list);
sec:
    if (g_queue_is_empty(&conn->secondary_list)) {
        g_queue_push_head(&conn->primary_list, ppkt);
        return;
    }
    spkt = g_queue_pop_head(&conn->secondary_list);

    if (ppkt->tcp_seq == ppkt->seq_end) {
        colo_release_primary_pkt(s, ppkt);
        ppkt = NULL;
    }

    if (ppkt && conn->compare_seq && !after(ppkt->seq_end, conn->compare_seq)) {
        trace_colo_compare_main("pri: this packet has compared");
        colo_release_primary_pkt(s, ppkt);
        ppkt = NULL;
    }

    if (spkt->tcp_seq == spkt->seq_end) {
        packet_destroy(spkt, NULL);
        if (!ppkt) {
            goto pri;
        } else {
            goto sec;
        }
    } else {
        if (conn->compare_seq && !after(spkt->seq_end, conn->compare_seq)) {
            trace_colo_compare_main("sec: this packet has compared");
            packet_destroy(spkt, NULL);
            if (!ppkt) {
                goto pri;
            } else {
                goto sec;
            }
        }
        if (!ppkt) {
            g_queue_push_head(&conn->secondary_list, spkt);
            goto pri;
        }
    }

    if (colo_mark_tcp_pkt(ppkt, spkt, &mark, min_ack)) {
        trace_colo_compare_tcp_info("pri",
                                    ppkt->tcp_seq, ppkt->tcp_ack,
                                    ppkt->header_size, ppkt->payload_size,
                                    ppkt->offset, ppkt->flags);

        trace_colo_compare_tcp_info("sec",
                                    spkt->tcp_seq, spkt->tcp_ack,
                                    spkt->header_size, spkt->payload_size,
                                    spkt->offset, spkt->flags);

        if (mark == COLO_COMPARE_FREE_PRIMARY) {
            conn->compare_seq = ppkt->seq_end;
            colo_release_primary_pkt(s, ppkt);
            g_queue_push_head(&conn->secondary_list, spkt);
            goto pri;
        }
        if (mark == COLO_COMPARE_FREE_SECONDARY) {
            conn->compare_seq = spkt->seq_end;
            packet_destroy(spkt, NULL);
            goto sec;
        }
        if (mark == (COLO_COMPARE_FREE_PRIMARY | COLO_COMPARE_FREE_SECONDARY)) {
            conn->compare_seq = ppkt->seq_end;
            colo_release_primary_pkt(s, ppkt);
            packet_destroy(spkt, NULL);
            goto pri;
        }
    } else {
        g_queue_push_head(&conn->primary_list, ppkt);
        g_queue_push_head(&conn->secondary_list, spkt);

        qemu_hexdump((char *)ppkt->data, stderr,
                     "colo-compare ppkt", ppkt->size);
        qemu_hexdump((char *)spkt->data, stderr,
                     "colo-compare spkt", spkt->size);

        colo_compare_inconsistency_notify(s);
    }
}


/*
 * Called from the compare thread on the primary
 * for compare udp packet
 */
static int colo_packet_compare_udp(Packet *spkt, Packet *ppkt)
{
    uint16_t network_header_length = ppkt->ip->ip_hl << 2;
    uint16_t offset = network_header_length + ETH_HLEN + ppkt->vnet_hdr_len;

    trace_colo_compare_main("compare udp");

    /*
     * Because of ppkt and spkt are both in the same connection,
     * The ppkt's src ip, dst ip, src port, dst port, ip_proto all are
     * same with spkt. In addition, IP header's Identification is a random
     * field, we can handle it in IP fragmentation function later.
     * COLO just concern the response net packet payload from primary guest
     * and secondary guest are same or not, So we ignored all IP header include
     * other field like TOS,TTL,IP Checksum. we only need to compare
     * the ip payload here.
     */
    if (ppkt->size != spkt->size) {
        trace_colo_compare_main("UDP: payload size of packets are different");
        return -1;
    }
    if (colo_compare_packet_payload(ppkt, spkt, offset, offset,
                                    ppkt->size - offset)) {
        trace_colo_compare_udp_miscompare("primary pkt size", ppkt->size);
        trace_colo_compare_udp_miscompare("Secondary pkt size", spkt->size);
        if (trace_event_get_state_backends(TRACE_COLO_COMPARE_MISCOMPARE)) {
            qemu_hexdump((char *)ppkt->data, stderr, "colo-compare pri pkt",
                         ppkt->size);
            qemu_hexdump((char *)spkt->data, stderr, "colo-compare sec pkt",
                         spkt->size);
        }
        return -1;
    } else {
        return 0;
    }
}

/*
 * Called from the compare thread on the primary
 * for compare icmp packet
 */
static int colo_packet_compare_icmp(Packet *spkt, Packet *ppkt)
{
    uint16_t network_header_length = ppkt->ip->ip_hl << 2;
    uint16_t offset = network_header_length + ETH_HLEN + ppkt->vnet_hdr_len;

    trace_colo_compare_main("compare icmp");

    /*
     * Because of ppkt and spkt are both in the same connection,
     * The ppkt's src ip, dst ip, src port, dst port, ip_proto all are
     * same with spkt. In addition, IP header's Identification is a random
     * field, we can handle it in IP fragmentation function later.
     * COLO just concern the response net packet payload from primary guest
     * and secondary guest are same or not, So we ignored all IP header include
     * other field like TOS,TTL,IP Checksum. we only need to compare
     * the ip payload here.
     */
    if (ppkt->size != spkt->size) {
        trace_colo_compare_main("ICMP: payload size of packets are different");
        return -1;
    }
    if (colo_compare_packet_payload(ppkt, spkt, offset, offset,
                                    ppkt->size - offset)) {
        trace_colo_compare_icmp_miscompare("primary pkt size",
                                           ppkt->size);
        trace_colo_compare_icmp_miscompare("Secondary pkt size",
                                           spkt->size);
        if (trace_event_get_state_backends(TRACE_COLO_COMPARE_MISCOMPARE)) {
            qemu_hexdump((char *)ppkt->data, stderr, "colo-compare pri pkt",
                         ppkt->size);
            qemu_hexdump((char *)spkt->data, stderr, "colo-compare sec pkt",
                         spkt->size);
        }
        return -1;
    } else {
        return 0;
    }
}

/*
 * Called from the compare thread on the primary
 * for compare other packet
 */
static int colo_packet_compare_other(Packet *spkt, Packet *ppkt)
{
    uint16_t offset = ppkt->vnet_hdr_len;

    trace_colo_compare_main("compare other");
    if (trace_event_get_state_backends(TRACE_COLO_COMPARE_MISCOMPARE)) {
        char pri_ip_src[20], pri_ip_dst[20], sec_ip_src[20], sec_ip_dst[20];

        strcpy(pri_ip_src, inet_ntoa(ppkt->ip->ip_src));
        strcpy(pri_ip_dst, inet_ntoa(ppkt->ip->ip_dst));
        strcpy(sec_ip_src, inet_ntoa(spkt->ip->ip_src));
        strcpy(sec_ip_dst, inet_ntoa(spkt->ip->ip_dst));

        trace_colo_compare_ip_info(ppkt->size, pri_ip_src,
                                   pri_ip_dst, spkt->size,
                                   sec_ip_src, sec_ip_dst);
    }

    if (ppkt->size != spkt->size) {
        trace_colo_compare_main("Other: payload size of packets are different");
        return -1;
    }
    return colo_compare_packet_payload(ppkt, spkt, offset, offset,
                                       ppkt->size - offset);
}

static int colo_old_packet_check_one(Packet *pkt, int64_t *check_time)
{
    int64_t now = qemu_clock_get_ms(QEMU_CLOCK_HOST);

    if ((now - pkt->creation_ms) > (*check_time)) {
        trace_colo_old_packet_check_found(pkt->creation_ms);
        return 0;
    } else {
        return 1;
    }
}

void colo_compare_register_notifier(Notifier *notify)
{
    notifier_list_add(&colo_compare_notifiers, notify);
}

void colo_compare_unregister_notifier(Notifier *notify)
{
    notifier_remove(notify);
}

static int colo_old_packet_check_one_conn(Connection *conn,
                                          CompareState *s)
{
    GList *result = NULL;
    int64_t check_time = REGULAR_PACKET_CHECK_MS;

    result = g_queue_find_custom(&conn->primary_list,
                                 &check_time,
                                 (GCompareFunc)colo_old_packet_check_one);

    if (result) {
        /* Do checkpoint will flush old packet */
        colo_compare_inconsistency_notify(s);
        return 0;
    }

    return 1;
}

/*
 * Look for old packets that the secondary hasn't matched,
 * if we have some then we have to checkpoint to wake
 * the secondary up.
 */
static void colo_old_packet_check(void *opaque)
{
    CompareState *s = opaque;

    /*
     * If we find one old packet, stop finding job and notify
     * COLO frame do checkpoint.
     */
    g_queue_find_custom(&s->conn_list, s,
                        (GCompareFunc)colo_old_packet_check_one_conn);
}

static void colo_compare_packet(CompareState *s, Connection *conn,
                                int (*HandlePacket)(Packet *spkt,
                                Packet *ppkt))
{
    Packet *pkt = NULL;
    GList *result = NULL;

    while (!g_queue_is_empty(&conn->primary_list) &&
           !g_queue_is_empty(&conn->secondary_list)) {
        pkt = g_queue_pop_head(&conn->primary_list);
        result = g_queue_find_custom(&conn->secondary_list,
                 pkt, (GCompareFunc)HandlePacket);

        if (result) {
            colo_release_primary_pkt(s, pkt);
            g_queue_remove(&conn->secondary_list, result->data);
        } else {
            /*
             * If one packet arrive late, the secondary_list or
             * primary_list will be empty, so we can't compare it
             * until next comparison. If the packets in the list are
             * timeout, it will trigger a checkpoint request.
             */
            trace_colo_compare_main("packet different");
            g_queue_push_head(&conn->primary_list, pkt);

            colo_compare_inconsistency_notify(s);
            break;
        }
    }
}

/*
 * Called from the compare thread on the primary
 * for compare packet with secondary list of the
 * specified connection when a new packet was
 * queued to it.
 */
static void colo_compare_connection(void *opaque, void *user_data)
{
    CompareState *s = user_data;
    Connection *conn = opaque;

    switch (conn->ip_proto) {
    case IPPROTO_TCP:
        colo_compare_tcp(s, conn);
        break;
    case IPPROTO_UDP:
        colo_compare_packet(s, conn, colo_packet_compare_udp);
        break;
    case IPPROTO_ICMP:
        colo_compare_packet(s, conn, colo_packet_compare_icmp);
        break;
    default:
        colo_compare_packet(s, conn, colo_packet_compare_other);
        break;
    }
}

static int compare_chr_send(CompareState *s,
                            const uint8_t *buf,
                            uint32_t size,
                            uint32_t vnet_hdr_len,
                            bool notify_remote_frame)
{
    int ret = 0;
    uint32_t len = htonl(size);

    if (!size) {
        return 0;
    }

    if (notify_remote_frame) {
        ret = qemu_chr_fe_write_all(&s->chr_notify_dev,
                                    (uint8_t *)&len,
                                    sizeof(len));
    } else {
        ret = qemu_chr_fe_write_all(&s->chr_out, (uint8_t *)&len, sizeof(len));
    }

    if (ret != sizeof(len)) {
        goto err;
    }

    if (s->vnet_hdr) {
        /*
         * We send vnet header len make other module(like filter-redirector)
         * know how to parse net packet correctly.
         */
        len = htonl(vnet_hdr_len);

        if (!notify_remote_frame) {
            ret = qemu_chr_fe_write_all(&s->chr_out,
                                        (uint8_t *)&len,
                                        sizeof(len));
        }

        if (ret != sizeof(len)) {
            goto err;
        }
    }

    if (notify_remote_frame) {
        ret = qemu_chr_fe_write_all(&s->chr_notify_dev,
                                    (uint8_t *)buf,
                                    size);
    } else {
        ret = qemu_chr_fe_write_all(&s->chr_out, (uint8_t *)buf, size);
    }

    if (ret != size) {
        goto err;
    }

    return 0;

err:
    return ret < 0 ? ret : -EIO;
}

static int compare_chr_can_read(void *opaque)
{
    return COMPARE_READ_LEN_MAX;
}

/*
 * Called from the main thread on the primary for packets
 * arriving over the socket from the primary.
 */
static void compare_pri_chr_in(void *opaque, const uint8_t *buf, int size)
{
    CompareState *s = COLO_COMPARE(opaque);
    int ret;

    ret = net_fill_rstate(&s->pri_rs, buf, size);
    if (ret == -1) {
        qemu_chr_fe_set_handlers(&s->chr_pri_in, NULL, NULL, NULL, NULL,
                                 NULL, NULL, true);
        error_report("colo-compare primary_in error");
    }
}

/*
 * Called from the main thread on the primary for packets
 * arriving over the socket from the secondary.
 */
static void compare_sec_chr_in(void *opaque, const uint8_t *buf, int size)
{
    CompareState *s = COLO_COMPARE(opaque);
    int ret;

    ret = net_fill_rstate(&s->sec_rs, buf, size);
    if (ret == -1) {
        qemu_chr_fe_set_handlers(&s->chr_sec_in, NULL, NULL, NULL, NULL,
                                 NULL, NULL, true);
        error_report("colo-compare secondary_in error");
    }
}

static void compare_notify_chr(void *opaque, const uint8_t *buf, int size)
{
    CompareState *s = COLO_COMPARE(opaque);
    int ret;

    ret = net_fill_rstate(&s->notify_rs, buf, size);
    if (ret == -1) {
        qemu_chr_fe_set_handlers(&s->chr_notify_dev, NULL, NULL, NULL, NULL,
                                 NULL, NULL, true);
        error_report("colo-compare notify_dev error");
    }
}

/*
 * Check old packet regularly so it can watch for any packets
 * that the secondary hasn't produced equivalents of.
 */
static void check_old_packet_regular(void *opaque)
{
    CompareState *s = opaque;

    /* if have old packet we will notify checkpoint */
    colo_old_packet_check(s);
    timer_mod(s->packet_check_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) +
                REGULAR_PACKET_CHECK_MS);
}

/* Public API, Used for COLO frame to notify compare event */
void colo_notify_compares_event(void *opaque, int event, Error **errp)
{
    CompareState *s;

    qemu_mutex_lock(&event_mtx);
    QTAILQ_FOREACH(s, &net_compares, next) {
        s->event = event;
        qemu_bh_schedule(s->event_bh);
        event_unhandled_count++;
    }
    /* Wait all compare threads to finish handling this event */
    while (event_unhandled_count > 0) {
        qemu_cond_wait(&event_complete_cond, &event_mtx);
    }

    qemu_mutex_unlock(&event_mtx);
}

static void colo_compare_timer_init(CompareState *s)
{
    AioContext *ctx = iothread_get_aio_context(s->iothread);

    s->packet_check_timer = aio_timer_new(ctx, QEMU_CLOCK_VIRTUAL,
                                SCALE_MS, check_old_packet_regular,
                                s);
    timer_mod(s->packet_check_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) +
                    REGULAR_PACKET_CHECK_MS);
}

static void colo_compare_timer_del(CompareState *s)
{
    if (s->packet_check_timer) {
        timer_del(s->packet_check_timer);
        timer_free(s->packet_check_timer);
        s->packet_check_timer = NULL;
    }
 }

static void colo_flush_packets(void *opaque, void *user_data);

static void colo_compare_handle_event(void *opaque)
{
    CompareState *s = opaque;

    switch (s->event) {
    case COLO_EVENT_CHECKPOINT:
        g_queue_foreach(&s->conn_list, colo_flush_packets, s);
        break;
    case COLO_EVENT_FAILOVER:
        break;
    default:
        break;
    }

    qemu_mutex_lock(&event_mtx);
    assert(event_unhandled_count > 0);
    event_unhandled_count--;
    qemu_cond_broadcast(&event_complete_cond);
    qemu_mutex_unlock(&event_mtx);
}

static void colo_compare_iothread(CompareState *s)
{
    object_ref(OBJECT(s->iothread));
    s->worker_context = iothread_get_g_main_context(s->iothread);

    qemu_chr_fe_set_handlers(&s->chr_pri_in, compare_chr_can_read,
                             compare_pri_chr_in, NULL, NULL,
                             s, s->worker_context, true);
    qemu_chr_fe_set_handlers(&s->chr_sec_in, compare_chr_can_read,
                             compare_sec_chr_in, NULL, NULL,
                             s, s->worker_context, true);
    if (s->notify_dev) {
        qemu_chr_fe_set_handlers(&s->chr_notify_dev, compare_chr_can_read,
                                 compare_notify_chr, NULL, NULL,
                                 s, s->worker_context, true);
    }

    colo_compare_timer_init(s);
    s->event_bh = qemu_bh_new(colo_compare_handle_event, s);
}

static char *compare_get_pri_indev(Object *obj, Error **errp)
{
    CompareState *s = COLO_COMPARE(obj);

    return g_strdup(s->pri_indev);
}

static void compare_set_pri_indev(Object *obj, const char *value, Error **errp)
{
    CompareState *s = COLO_COMPARE(obj);

    g_free(s->pri_indev);
    s->pri_indev = g_strdup(value);
}

static char *compare_get_sec_indev(Object *obj, Error **errp)
{
    CompareState *s = COLO_COMPARE(obj);

    return g_strdup(s->sec_indev);
}

static void compare_set_sec_indev(Object *obj, const char *value, Error **errp)
{
    CompareState *s = COLO_COMPARE(obj);

    g_free(s->sec_indev);
    s->sec_indev = g_strdup(value);
}

static char *compare_get_outdev(Object *obj, Error **errp)
{
    CompareState *s = COLO_COMPARE(obj);

    return g_strdup(s->outdev);
}

static void compare_set_outdev(Object *obj, const char *value, Error **errp)
{
    CompareState *s = COLO_COMPARE(obj);

    g_free(s->outdev);
    s->outdev = g_strdup(value);
}

static bool compare_get_vnet_hdr(Object *obj, Error **errp)
{
    CompareState *s = COLO_COMPARE(obj);

    return s->vnet_hdr;
}

static void compare_set_vnet_hdr(Object *obj,
                                 bool value,
                                 Error **errp)
{
    CompareState *s = COLO_COMPARE(obj);

    s->vnet_hdr = value;
}

static char *compare_get_notify_dev(Object *obj, Error **errp)
{
    CompareState *s = COLO_COMPARE(obj);

    return g_strdup(s->notify_dev);
}

static void compare_set_notify_dev(Object *obj, const char *value, Error **errp)
{
    CompareState *s = COLO_COMPARE(obj);

    g_free(s->notify_dev);
    s->notify_dev = g_strdup(value);
}

static void compare_pri_rs_finalize(SocketReadState *pri_rs)
{
    CompareState *s = container_of(pri_rs, CompareState, pri_rs);
    Connection *conn = NULL;

    if (packet_enqueue(s, PRIMARY_IN, &conn)) {
        trace_colo_compare_main("primary: unsupported packet in");
        compare_chr_send(s,
                         pri_rs->buf,
                         pri_rs->packet_len,
                         pri_rs->vnet_hdr_len,
                         false);
    } else {
        /* compare packet in the specified connection */
        colo_compare_connection(conn, s);
    }
}

static void compare_sec_rs_finalize(SocketReadState *sec_rs)
{
    CompareState *s = container_of(sec_rs, CompareState, sec_rs);
    Connection *conn = NULL;

    if (packet_enqueue(s, SECONDARY_IN, &conn)) {
        trace_colo_compare_main("secondary: unsupported packet in");
    } else {
        /* compare packet in the specified connection */
        colo_compare_connection(conn, s);
    }
}

static void compare_notify_rs_finalize(SocketReadState *notify_rs)
{
    CompareState *s = container_of(notify_rs, CompareState, notify_rs);

    const char msg[] = "COLO_COMPARE_GET_XEN_INIT";
    int ret;

    if (packet_matches_str("COLO_USERSPACE_PROXY_INIT",
                           notify_rs->buf,
                           notify_rs->packet_len)) {
        ret = compare_chr_send(s, (uint8_t *)msg, strlen(msg), 0, true);
        if (ret < 0) {
            error_report("Notify Xen COLO-frame INIT failed");
        }
    } else if (packet_matches_str("COLO_CHECKPOINT",
                                  notify_rs->buf,
                                  notify_rs->packet_len)) {
        /* colo-compare do checkpoint, flush pri packet and remove sec packet */
        g_queue_foreach(&s->conn_list, colo_flush_packets, s);
    } else {
        error_report("COLO compare got unsupported instruction");
    }
}

/*
 * Return 0 is success.
 * Return 1 is failed.
 */
static int find_and_check_chardev(Chardev **chr,
                                  char *chr_name,
                                  Error **errp)
{
    *chr = qemu_chr_find(chr_name);
    if (*chr == NULL) {
        error_setg(errp, "Device '%s' not found",
                   chr_name);
        return 1;
    }

    if (!qemu_chr_has_feature(*chr, QEMU_CHAR_FEATURE_RECONNECTABLE)) {
        error_setg(errp, "chardev \"%s\" is not reconnectable",
                   chr_name);
        return 1;
    }

    if (!qemu_chr_has_feature(*chr, QEMU_CHAR_FEATURE_GCONTEXT)) {
        error_setg(errp, "chardev \"%s\" cannot switch context",
                   chr_name);
        return 1;
    }

    return 0;
}

/*
 * Called from the main thread on the primary
 * to setup colo-compare.
 */
static void colo_compare_complete(UserCreatable *uc, Error **errp)
{
    CompareState *s = COLO_COMPARE(uc);
    Chardev *chr;

    if (!s->pri_indev || !s->sec_indev || !s->outdev || !s->iothread) {
        error_setg(errp, "colo compare needs 'primary_in' ,"
                   "'secondary_in','outdev','iothread' property set");
        return;
    } else if (!strcmp(s->pri_indev, s->outdev) ||
               !strcmp(s->sec_indev, s->outdev) ||
               !strcmp(s->pri_indev, s->sec_indev)) {
        error_setg(errp, "'indev' and 'outdev' could not be same "
                   "for compare module");
        return;
    }

    if (find_and_check_chardev(&chr, s->pri_indev, errp) ||
        !qemu_chr_fe_init(&s->chr_pri_in, chr, errp)) {
        return;
    }

    if (find_and_check_chardev(&chr, s->sec_indev, errp) ||
        !qemu_chr_fe_init(&s->chr_sec_in, chr, errp)) {
        return;
    }

    if (find_and_check_chardev(&chr, s->outdev, errp) ||
        !qemu_chr_fe_init(&s->chr_out, chr, errp)) {
        return;
    }

    net_socket_rs_init(&s->pri_rs, compare_pri_rs_finalize, s->vnet_hdr);
    net_socket_rs_init(&s->sec_rs, compare_sec_rs_finalize, s->vnet_hdr);

    /* Try to enable remote notify chardev, currently just for Xen COLO */
    if (s->notify_dev) {
        if (find_and_check_chardev(&chr, s->notify_dev, errp) ||
            !qemu_chr_fe_init(&s->chr_notify_dev, chr, errp)) {
            return;
        }

        net_socket_rs_init(&s->notify_rs, compare_notify_rs_finalize,
                           s->vnet_hdr);
    }

    QTAILQ_INSERT_TAIL(&net_compares, s, next);

    g_queue_init(&s->conn_list);

    qemu_mutex_init(&event_mtx);
    qemu_cond_init(&event_complete_cond);

    s->connection_track_table = g_hash_table_new_full(connection_key_hash,
                                                      connection_key_equal,
                                                      g_free,
                                                      connection_destroy);

    colo_compare_iothread(s);
    return;
}

static void colo_flush_packets(void *opaque, void *user_data)
{
    CompareState *s = user_data;
    Connection *conn = opaque;
    Packet *pkt = NULL;

    while (!g_queue_is_empty(&conn->primary_list)) {
        pkt = g_queue_pop_head(&conn->primary_list);
        compare_chr_send(s,
                         pkt->data,
                         pkt->size,
                         pkt->vnet_hdr_len,
                         false);
        packet_destroy(pkt, NULL);
    }
    while (!g_queue_is_empty(&conn->secondary_list)) {
        pkt = g_queue_pop_head(&conn->secondary_list);
        packet_destroy(pkt, NULL);
    }
}

static void colo_compare_class_init(ObjectClass *oc, void *data)
{
    UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);

    ucc->complete = colo_compare_complete;
}

static void colo_compare_init(Object *obj)
{
    CompareState *s = COLO_COMPARE(obj);

    object_property_add_str(obj, "primary_in",
                            compare_get_pri_indev, compare_set_pri_indev,
                            NULL);
    object_property_add_str(obj, "secondary_in",
                            compare_get_sec_indev, compare_set_sec_indev,
                            NULL);
    object_property_add_str(obj, "outdev",
                            compare_get_outdev, compare_set_outdev,
                            NULL);
    object_property_add_link(obj, "iothread", TYPE_IOTHREAD,
                            (Object **)&s->iothread,
                            object_property_allow_set_link,
                            OBJ_PROP_LINK_STRONG, NULL);
    /* This parameter just for Xen COLO */
    object_property_add_str(obj, "notify_dev",
                            compare_get_notify_dev, compare_set_notify_dev,
                            NULL);

    s->vnet_hdr = false;
    object_property_add_bool(obj, "vnet_hdr_support", compare_get_vnet_hdr,
                             compare_set_vnet_hdr, NULL);
}

static void colo_compare_finalize(Object *obj)
{
    CompareState *s = COLO_COMPARE(obj);
    CompareState *tmp = NULL;

    qemu_chr_fe_deinit(&s->chr_pri_in, false);
    qemu_chr_fe_deinit(&s->chr_sec_in, false);
    qemu_chr_fe_deinit(&s->chr_out, false);
    if (s->notify_dev) {
        qemu_chr_fe_deinit(&s->chr_notify_dev, false);
    }

    if (s->iothread) {
        colo_compare_timer_del(s);
    }

    qemu_bh_delete(s->event_bh);

    QTAILQ_FOREACH(tmp, &net_compares, next) {
        if (tmp == s) {
            QTAILQ_REMOVE(&net_compares, s, next);
            break;
        }
    }

    /* Release all unhandled packets after compare thead exited */
    g_queue_foreach(&s->conn_list, colo_flush_packets, s);

    g_queue_clear(&s->conn_list);

    if (s->connection_track_table) {
        g_hash_table_destroy(s->connection_track_table);
    }

    if (s->iothread) {
        object_unref(OBJECT(s->iothread));
    }

    qemu_mutex_destroy(&event_mtx);
    qemu_cond_destroy(&event_complete_cond);

    g_free(s->pri_indev);
    g_free(s->sec_indev);
    g_free(s->outdev);
    g_free(s->notify_dev);
}

static const TypeInfo colo_compare_info = {
    .name = TYPE_COLO_COMPARE,
    .parent = TYPE_OBJECT,
    .instance_size = sizeof(CompareState),
    .instance_init = colo_compare_init,
    .instance_finalize = colo_compare_finalize,
    .class_size = sizeof(CompareClass),
    .class_init = colo_compare_class_init,
    .interfaces = (InterfaceInfo[]) {
        { TYPE_USER_CREATABLE },
        { }
    }
};

static void register_types(void)
{
    type_register_static(&colo_compare_info);
}

type_init(register_types);