xref: /openbmc/qemu/net/colo-compare.c (revision 5e437d3c)
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-common.h"
17 #include "qemu/error-report.h"
18 #include "trace.h"
19 #include "qapi/error.h"
20 #include "net/net.h"
21 #include "net/eth.h"
22 #include "qom/object_interfaces.h"
23 #include "qemu/iov.h"
24 #include "qom/object.h"
25 #include "net/queue.h"
26 #include "chardev/char-fe.h"
27 #include "qemu/sockets.h"
28 #include "colo.h"
29 #include "sysemu/iothread.h"
30 #include "net/colo-compare.h"
31 #include "migration/colo.h"
32 #include "migration/migration.h"
33 #include "util.h"
34 
35 #include "block/aio-wait.h"
36 #include "qemu/coroutine.h"
37 
38 #define TYPE_COLO_COMPARE "colo-compare"
39 typedef struct CompareState CompareState;
40 DECLARE_INSTANCE_CHECKER(CompareState, COLO_COMPARE,
41                          TYPE_COLO_COMPARE)
42 
43 static QTAILQ_HEAD(, CompareState) net_compares =
44        QTAILQ_HEAD_INITIALIZER(net_compares);
45 
46 static NotifierList colo_compare_notifiers =
47     NOTIFIER_LIST_INITIALIZER(colo_compare_notifiers);
48 
49 #define COMPARE_READ_LEN_MAX NET_BUFSIZE
50 #define MAX_QUEUE_SIZE 1024
51 
52 #define COLO_COMPARE_FREE_PRIMARY     0x01
53 #define COLO_COMPARE_FREE_SECONDARY   0x02
54 
55 #define REGULAR_PACKET_CHECK_MS 1000
56 #define DEFAULT_TIME_OUT_MS 3000
57 
58 /* #define DEBUG_COLO_PACKETS */
59 
60 static QemuMutex colo_compare_mutex;
61 static bool colo_compare_active;
62 static QemuMutex event_mtx;
63 static QemuCond event_complete_cond;
64 static int event_unhandled_count;
65 static uint32_t max_queue_size;
66 
67 /*
68  *  + CompareState ++
69  *  |               |
70  *  +---------------+   +---------------+         +---------------+
71  *  |   conn list   + - >      conn     + ------- >      conn     + -- > ......
72  *  +---------------+   +---------------+         +---------------+
73  *  |               |     |           |             |          |
74  *  +---------------+ +---v----+  +---v----+    +---v----+ +---v----+
75  *                    |primary |  |secondary    |primary | |secondary
76  *                    |packet  |  |packet  +    |packet  | |packet  +
77  *                    +--------+  +--------+    +--------+ +--------+
78  *                        |           |             |          |
79  *                    +---v----+  +---v----+    +---v----+ +---v----+
80  *                    |primary |  |secondary    |primary | |secondary
81  *                    |packet  |  |packet  +    |packet  | |packet  +
82  *                    +--------+  +--------+    +--------+ +--------+
83  *                        |           |             |          |
84  *                    +---v----+  +---v----+    +---v----+ +---v----+
85  *                    |primary |  |secondary    |primary | |secondary
86  *                    |packet  |  |packet  +    |packet  | |packet  +
87  *                    +--------+  +--------+    +--------+ +--------+
88  */
89 
90 typedef struct SendCo {
91     Coroutine *co;
92     struct CompareState *s;
93     CharBackend *chr;
94     GQueue send_list;
95     bool notify_remote_frame;
96     bool done;
97     int ret;
98 } SendCo;
99 
100 typedef struct SendEntry {
101     uint32_t size;
102     uint32_t vnet_hdr_len;
103     uint8_t *buf;
104 } SendEntry;
105 
106 struct CompareState {
107     Object parent;
108 
109     char *pri_indev;
110     char *sec_indev;
111     char *outdev;
112     char *notify_dev;
113     CharBackend chr_pri_in;
114     CharBackend chr_sec_in;
115     CharBackend chr_out;
116     CharBackend chr_notify_dev;
117     SocketReadState pri_rs;
118     SocketReadState sec_rs;
119     SocketReadState notify_rs;
120     SendCo out_sendco;
121     SendCo notify_sendco;
122     bool vnet_hdr;
123     uint64_t compare_timeout;
124     uint32_t expired_scan_cycle;
125 
126     /*
127      * Record the connection that through the NIC
128      * Element type: Connection
129      */
130     GQueue conn_list;
131     /* Record the connection without repetition */
132     GHashTable *connection_track_table;
133 
134     IOThread *iothread;
135     GMainContext *worker_context;
136     QEMUTimer *packet_check_timer;
137 
138     QEMUBH *event_bh;
139     enum colo_event event;
140 
141     QTAILQ_ENTRY(CompareState) next;
142 };
143 
144 typedef struct CompareClass {
145     ObjectClass parent_class;
146 } CompareClass;
147 
148 enum {
149     PRIMARY_IN = 0,
150     SECONDARY_IN,
151 };
152 
153 static const char *colo_mode[] = {
154     [PRIMARY_IN] = "primary",
155     [SECONDARY_IN] = "secondary",
156 };
157 
158 static int compare_chr_send(CompareState *s,
159                             uint8_t *buf,
160                             uint32_t size,
161                             uint32_t vnet_hdr_len,
162                             bool notify_remote_frame,
163                             bool zero_copy);
164 
165 static bool packet_matches_str(const char *str,
166                                const uint8_t *buf,
167                                uint32_t packet_len)
168 {
169     if (packet_len != strlen(str)) {
170         return false;
171     }
172 
173     return !memcmp(str, buf, strlen(str));
174 }
175 
176 static void notify_remote_frame(CompareState *s)
177 {
178     char msg[] = "DO_CHECKPOINT";
179     int ret = 0;
180 
181     ret = compare_chr_send(s, (uint8_t *)msg, strlen(msg), 0, true, false);
182     if (ret < 0) {
183         error_report("Notify Xen COLO-frame failed");
184     }
185 }
186 
187 static void colo_compare_inconsistency_notify(CompareState *s)
188 {
189     if (s->notify_dev) {
190         notify_remote_frame(s);
191     } else {
192         notifier_list_notify(&colo_compare_notifiers,
193                              migrate_get_current());
194     }
195 }
196 
197 /* Use restricted to colo_insert_packet() */
198 static gint seq_sorter(Packet *a, Packet *b, gpointer data)
199 {
200     return a->tcp_seq - b->tcp_seq;
201 }
202 
203 static void fill_pkt_tcp_info(void *data, uint32_t *max_ack)
204 {
205     Packet *pkt = data;
206     struct tcp_hdr *tcphd;
207 
208     tcphd = (struct tcp_hdr *)pkt->transport_header;
209 
210     pkt->tcp_seq = ntohl(tcphd->th_seq);
211     pkt->tcp_ack = ntohl(tcphd->th_ack);
212     *max_ack = *max_ack > pkt->tcp_ack ? *max_ack : pkt->tcp_ack;
213     pkt->header_size = pkt->transport_header - (uint8_t *)pkt->data
214                        + (tcphd->th_off << 2) - pkt->vnet_hdr_len;
215     pkt->payload_size = pkt->size - pkt->header_size;
216     pkt->seq_end = pkt->tcp_seq + pkt->payload_size;
217     pkt->flags = tcphd->th_flags;
218 }
219 
220 /*
221  * Return 1 on success, if return 0 means the
222  * packet will be dropped
223  */
224 static int colo_insert_packet(GQueue *queue, Packet *pkt, uint32_t *max_ack)
225 {
226     if (g_queue_get_length(queue) <= max_queue_size) {
227         if (pkt->ip->ip_p == IPPROTO_TCP) {
228             fill_pkt_tcp_info(pkt, max_ack);
229             g_queue_insert_sorted(queue,
230                                   pkt,
231                                   (GCompareDataFunc)seq_sorter,
232                                   NULL);
233         } else {
234             g_queue_push_tail(queue, pkt);
235         }
236         return 1;
237     }
238     return 0;
239 }
240 
241 /*
242  * Return 0 on success, if return -1 means the pkt
243  * is unsupported(arp and ipv6) and will be sent later
244  */
245 static int packet_enqueue(CompareState *s, int mode, Connection **con)
246 {
247     ConnectionKey key;
248     Packet *pkt = NULL;
249     Connection *conn;
250     int ret;
251 
252     if (mode == PRIMARY_IN) {
253         pkt = packet_new(s->pri_rs.buf,
254                          s->pri_rs.packet_len,
255                          s->pri_rs.vnet_hdr_len);
256     } else {
257         pkt = packet_new(s->sec_rs.buf,
258                          s->sec_rs.packet_len,
259                          s->sec_rs.vnet_hdr_len);
260     }
261 
262     if (parse_packet_early(pkt)) {
263         packet_destroy(pkt, NULL);
264         pkt = NULL;
265         return -1;
266     }
267     fill_connection_key(pkt, &key);
268 
269     conn = connection_get(s->connection_track_table,
270                           &key,
271                           &s->conn_list);
272 
273     if (!conn->processing) {
274         g_queue_push_tail(&s->conn_list, conn);
275         conn->processing = true;
276     }
277 
278     if (mode == PRIMARY_IN) {
279         ret = colo_insert_packet(&conn->primary_list, pkt, &conn->pack);
280     } else {
281         ret = colo_insert_packet(&conn->secondary_list, pkt, &conn->sack);
282     }
283 
284     if (!ret) {
285         trace_colo_compare_drop_packet(colo_mode[mode],
286             "queue size too big, drop packet");
287         packet_destroy(pkt, NULL);
288         pkt = NULL;
289     }
290 
291     *con = conn;
292 
293     return 0;
294 }
295 
296 static inline bool after(uint32_t seq1, uint32_t seq2)
297 {
298         return (int32_t)(seq1 - seq2) > 0;
299 }
300 
301 static void colo_release_primary_pkt(CompareState *s, Packet *pkt)
302 {
303     int ret;
304     ret = compare_chr_send(s,
305                            pkt->data,
306                            pkt->size,
307                            pkt->vnet_hdr_len,
308                            false,
309                            true);
310     if (ret < 0) {
311         error_report("colo send primary packet failed");
312     }
313     trace_colo_compare_main("packet same and release packet");
314     packet_destroy_partial(pkt, NULL);
315 }
316 
317 /*
318  * The IP packets sent by primary and secondary
319  * will be compared in here
320  * TODO support ip fragment, Out-Of-Order
321  * return:    0  means packet same
322  *            > 0 || < 0 means packet different
323  */
324 static int colo_compare_packet_payload(Packet *ppkt,
325                                        Packet *spkt,
326                                        uint16_t poffset,
327                                        uint16_t soffset,
328                                        uint16_t len)
329 
330 {
331     if (trace_event_get_state_backends(TRACE_COLO_COMPARE_IP_INFO)) {
332         char pri_ip_src[20], pri_ip_dst[20], sec_ip_src[20], sec_ip_dst[20];
333 
334         strcpy(pri_ip_src, inet_ntoa(ppkt->ip->ip_src));
335         strcpy(pri_ip_dst, inet_ntoa(ppkt->ip->ip_dst));
336         strcpy(sec_ip_src, inet_ntoa(spkt->ip->ip_src));
337         strcpy(sec_ip_dst, inet_ntoa(spkt->ip->ip_dst));
338 
339         trace_colo_compare_ip_info(ppkt->size, pri_ip_src,
340                                    pri_ip_dst, spkt->size,
341                                    sec_ip_src, sec_ip_dst);
342     }
343 
344     return memcmp(ppkt->data + poffset, spkt->data + soffset, len);
345 }
346 
347 /*
348  * return true means that the payload is consist and
349  * need to make the next comparison, false means do
350  * the checkpoint
351 */
352 static bool colo_mark_tcp_pkt(Packet *ppkt, Packet *spkt,
353                               int8_t *mark, uint32_t max_ack)
354 {
355     *mark = 0;
356 
357     if (ppkt->tcp_seq == spkt->tcp_seq && ppkt->seq_end == spkt->seq_end) {
358         if (!colo_compare_packet_payload(ppkt, spkt,
359                                         ppkt->header_size, spkt->header_size,
360                                         ppkt->payload_size)) {
361             *mark = COLO_COMPARE_FREE_SECONDARY | COLO_COMPARE_FREE_PRIMARY;
362             return true;
363         }
364     }
365 
366     /* one part of secondary packet payload still need to be compared */
367     if (!after(ppkt->seq_end, spkt->seq_end)) {
368         if (!colo_compare_packet_payload(ppkt, spkt,
369                                         ppkt->header_size + ppkt->offset,
370                                         spkt->header_size + spkt->offset,
371                                         ppkt->payload_size - ppkt->offset)) {
372             if (!after(ppkt->tcp_ack, max_ack)) {
373                 *mark = COLO_COMPARE_FREE_PRIMARY;
374                 spkt->offset += ppkt->payload_size - ppkt->offset;
375                 return true;
376             } else {
377                 /* secondary guest hasn't ack the data, don't send
378                  * out this packet
379                  */
380                 return false;
381             }
382         }
383     } else {
384         /* primary packet is longer than secondary packet, compare
385          * the same part and mark the primary packet offset
386          */
387         if (!colo_compare_packet_payload(ppkt, spkt,
388                                         ppkt->header_size + ppkt->offset,
389                                         spkt->header_size + spkt->offset,
390                                         spkt->payload_size - spkt->offset)) {
391             *mark = COLO_COMPARE_FREE_SECONDARY;
392             ppkt->offset += spkt->payload_size - spkt->offset;
393             return true;
394         }
395     }
396 
397     return false;
398 }
399 
400 static void colo_compare_tcp(CompareState *s, Connection *conn)
401 {
402     Packet *ppkt = NULL, *spkt = NULL;
403     int8_t mark;
404 
405     /*
406      * If ppkt and spkt have the same payload, but ppkt's ACK
407      * is greater than spkt's ACK, in this case we can not
408      * send the ppkt because it will cause the secondary guest
409      * to miss sending some data in the next. Therefore, we
410      * record the maximum ACK in the current queue at both
411      * primary side and secondary side. Only when the ack is
412      * less than the smaller of the two maximum ack, then we
413      * can ensure that the packet's payload is acknowledged by
414      * primary and secondary.
415     */
416     uint32_t min_ack = conn->pack > conn->sack ? conn->sack : conn->pack;
417 
418 pri:
419     if (g_queue_is_empty(&conn->primary_list)) {
420         return;
421     }
422     ppkt = g_queue_pop_head(&conn->primary_list);
423 sec:
424     if (g_queue_is_empty(&conn->secondary_list)) {
425         g_queue_push_head(&conn->primary_list, ppkt);
426         return;
427     }
428     spkt = g_queue_pop_head(&conn->secondary_list);
429 
430     if (ppkt->tcp_seq == ppkt->seq_end) {
431         colo_release_primary_pkt(s, ppkt);
432         ppkt = NULL;
433     }
434 
435     if (ppkt && conn->compare_seq && !after(ppkt->seq_end, conn->compare_seq)) {
436         trace_colo_compare_main("pri: this packet has compared");
437         colo_release_primary_pkt(s, ppkt);
438         ppkt = NULL;
439     }
440 
441     if (spkt->tcp_seq == spkt->seq_end) {
442         packet_destroy(spkt, NULL);
443         if (!ppkt) {
444             goto pri;
445         } else {
446             goto sec;
447         }
448     } else {
449         if (conn->compare_seq && !after(spkt->seq_end, conn->compare_seq)) {
450             trace_colo_compare_main("sec: this packet has compared");
451             packet_destroy(spkt, NULL);
452             if (!ppkt) {
453                 goto pri;
454             } else {
455                 goto sec;
456             }
457         }
458         if (!ppkt) {
459             g_queue_push_head(&conn->secondary_list, spkt);
460             goto pri;
461         }
462     }
463 
464     if (colo_mark_tcp_pkt(ppkt, spkt, &mark, min_ack)) {
465         trace_colo_compare_tcp_info("pri",
466                                     ppkt->tcp_seq, ppkt->tcp_ack,
467                                     ppkt->header_size, ppkt->payload_size,
468                                     ppkt->offset, ppkt->flags);
469 
470         trace_colo_compare_tcp_info("sec",
471                                     spkt->tcp_seq, spkt->tcp_ack,
472                                     spkt->header_size, spkt->payload_size,
473                                     spkt->offset, spkt->flags);
474 
475         if (mark == COLO_COMPARE_FREE_PRIMARY) {
476             conn->compare_seq = ppkt->seq_end;
477             colo_release_primary_pkt(s, ppkt);
478             g_queue_push_head(&conn->secondary_list, spkt);
479             goto pri;
480         } else if (mark == COLO_COMPARE_FREE_SECONDARY) {
481             conn->compare_seq = spkt->seq_end;
482             packet_destroy(spkt, NULL);
483             goto sec;
484         } else if (mark == (COLO_COMPARE_FREE_PRIMARY | COLO_COMPARE_FREE_SECONDARY)) {
485             conn->compare_seq = ppkt->seq_end;
486             colo_release_primary_pkt(s, ppkt);
487             packet_destroy(spkt, NULL);
488             goto pri;
489         }
490     } else {
491         g_queue_push_head(&conn->primary_list, ppkt);
492         g_queue_push_head(&conn->secondary_list, spkt);
493 
494 #ifdef DEBUG_COLO_PACKETS
495         qemu_hexdump(stderr, "colo-compare ppkt", ppkt->data, ppkt->size);
496         qemu_hexdump(stderr, "colo-compare spkt", spkt->data, spkt->size);
497 #endif
498 
499         colo_compare_inconsistency_notify(s);
500     }
501 }
502 
503 
504 /*
505  * Called from the compare thread on the primary
506  * for compare udp packet
507  */
508 static int colo_packet_compare_udp(Packet *spkt, Packet *ppkt)
509 {
510     uint16_t network_header_length = ppkt->ip->ip_hl << 2;
511     uint16_t offset = network_header_length + ETH_HLEN + ppkt->vnet_hdr_len;
512 
513     trace_colo_compare_main("compare udp");
514 
515     /*
516      * Because of ppkt and spkt are both in the same connection,
517      * The ppkt's src ip, dst ip, src port, dst port, ip_proto all are
518      * same with spkt. In addition, IP header's Identification is a random
519      * field, we can handle it in IP fragmentation function later.
520      * COLO just concern the response net packet payload from primary guest
521      * and secondary guest are same or not, So we ignored all IP header include
522      * other field like TOS,TTL,IP Checksum. we only need to compare
523      * the ip payload here.
524      */
525     if (ppkt->size != spkt->size) {
526         trace_colo_compare_main("UDP: payload size of packets are different");
527         return -1;
528     }
529     if (colo_compare_packet_payload(ppkt, spkt, offset, offset,
530                                     ppkt->size - offset)) {
531         trace_colo_compare_udp_miscompare("primary pkt size", ppkt->size);
532         trace_colo_compare_udp_miscompare("Secondary pkt size", spkt->size);
533 #ifdef DEBUG_COLO_PACKETS
534         qemu_hexdump(stderr, "colo-compare pri pkt", ppkt->data, ppkt->size);
535         qemu_hexdump(stderr, "colo-compare sec pkt", spkt->data, spkt->size);
536 #endif
537         return -1;
538     } else {
539         return 0;
540     }
541 }
542 
543 /*
544  * Called from the compare thread on the primary
545  * for compare icmp packet
546  */
547 static int colo_packet_compare_icmp(Packet *spkt, Packet *ppkt)
548 {
549     uint16_t network_header_length = ppkt->ip->ip_hl << 2;
550     uint16_t offset = network_header_length + ETH_HLEN + ppkt->vnet_hdr_len;
551 
552     trace_colo_compare_main("compare icmp");
553 
554     /*
555      * Because of ppkt and spkt are both in the same connection,
556      * The ppkt's src ip, dst ip, src port, dst port, ip_proto all are
557      * same with spkt. In addition, IP header's Identification is a random
558      * field, we can handle it in IP fragmentation function later.
559      * COLO just concern the response net packet payload from primary guest
560      * and secondary guest are same or not, So we ignored all IP header include
561      * other field like TOS,TTL,IP Checksum. we only need to compare
562      * the ip payload here.
563      */
564     if (ppkt->size != spkt->size) {
565         trace_colo_compare_main("ICMP: payload size of packets are different");
566         return -1;
567     }
568     if (colo_compare_packet_payload(ppkt, spkt, offset, offset,
569                                     ppkt->size - offset)) {
570         trace_colo_compare_icmp_miscompare("primary pkt size",
571                                            ppkt->size);
572         trace_colo_compare_icmp_miscompare("Secondary pkt size",
573                                            spkt->size);
574 #ifdef DEBUG_COLO_PACKETS
575         qemu_hexdump(stderr, "colo-compare pri pkt", ppkt->data, ppkt->size);
576         qemu_hexdump(stderr, "colo-compare sec pkt", spkt->data, spkt->size);
577 #endif
578         return -1;
579     } else {
580         return 0;
581     }
582 }
583 
584 /*
585  * Called from the compare thread on the primary
586  * for compare other packet
587  */
588 static int colo_packet_compare_other(Packet *spkt, Packet *ppkt)
589 {
590     uint16_t offset = ppkt->vnet_hdr_len;
591 
592     trace_colo_compare_main("compare other");
593     if (trace_event_get_state_backends(TRACE_COLO_COMPARE_IP_INFO)) {
594         char pri_ip_src[20], pri_ip_dst[20], sec_ip_src[20], sec_ip_dst[20];
595 
596         strcpy(pri_ip_src, inet_ntoa(ppkt->ip->ip_src));
597         strcpy(pri_ip_dst, inet_ntoa(ppkt->ip->ip_dst));
598         strcpy(sec_ip_src, inet_ntoa(spkt->ip->ip_src));
599         strcpy(sec_ip_dst, inet_ntoa(spkt->ip->ip_dst));
600 
601         trace_colo_compare_ip_info(ppkt->size, pri_ip_src,
602                                    pri_ip_dst, spkt->size,
603                                    sec_ip_src, sec_ip_dst);
604     }
605 
606     if (ppkt->size != spkt->size) {
607         trace_colo_compare_main("Other: payload size of packets are different");
608         return -1;
609     }
610     return colo_compare_packet_payload(ppkt, spkt, offset, offset,
611                                        ppkt->size - offset);
612 }
613 
614 static int colo_old_packet_check_one(Packet *pkt, int64_t *check_time)
615 {
616     int64_t now = qemu_clock_get_ms(QEMU_CLOCK_HOST);
617 
618     if ((now - pkt->creation_ms) > (*check_time)) {
619         trace_colo_old_packet_check_found(pkt->creation_ms);
620         return 0;
621     } else {
622         return 1;
623     }
624 }
625 
626 void colo_compare_register_notifier(Notifier *notify)
627 {
628     notifier_list_add(&colo_compare_notifiers, notify);
629 }
630 
631 void colo_compare_unregister_notifier(Notifier *notify)
632 {
633     notifier_remove(notify);
634 }
635 
636 static int colo_old_packet_check_one_conn(Connection *conn,
637                                           CompareState *s)
638 {
639     if (!g_queue_is_empty(&conn->primary_list)) {
640         if (g_queue_find_custom(&conn->primary_list,
641                                 &s->compare_timeout,
642                                 (GCompareFunc)colo_old_packet_check_one))
643             goto out;
644     }
645 
646     if (!g_queue_is_empty(&conn->secondary_list)) {
647         if (g_queue_find_custom(&conn->secondary_list,
648                                 &s->compare_timeout,
649                                 (GCompareFunc)colo_old_packet_check_one))
650             goto out;
651     }
652 
653     return 1;
654 
655 out:
656     /* Do checkpoint will flush old packet */
657     colo_compare_inconsistency_notify(s);
658     return 0;
659 }
660 
661 /*
662  * Look for old packets that the secondary hasn't matched,
663  * if we have some then we have to checkpoint to wake
664  * the secondary up.
665  */
666 static void colo_old_packet_check(void *opaque)
667 {
668     CompareState *s = opaque;
669 
670     /*
671      * If we find one old packet, stop finding job and notify
672      * COLO frame do checkpoint.
673      */
674     g_queue_find_custom(&s->conn_list, s,
675                         (GCompareFunc)colo_old_packet_check_one_conn);
676 }
677 
678 static void colo_compare_packet(CompareState *s, Connection *conn,
679                                 int (*HandlePacket)(Packet *spkt,
680                                 Packet *ppkt))
681 {
682     Packet *pkt = NULL;
683     GList *result = NULL;
684 
685     while (!g_queue_is_empty(&conn->primary_list) &&
686            !g_queue_is_empty(&conn->secondary_list)) {
687         pkt = g_queue_pop_head(&conn->primary_list);
688         result = g_queue_find_custom(&conn->secondary_list,
689                  pkt, (GCompareFunc)HandlePacket);
690 
691         if (result) {
692             colo_release_primary_pkt(s, pkt);
693             packet_destroy(result->data, NULL);
694             g_queue_delete_link(&conn->secondary_list, result);
695         } else {
696             /*
697              * If one packet arrive late, the secondary_list or
698              * primary_list will be empty, so we can't compare it
699              * until next comparison. If the packets in the list are
700              * timeout, it will trigger a checkpoint request.
701              */
702             trace_colo_compare_main("packet different");
703             g_queue_push_head(&conn->primary_list, pkt);
704 
705             colo_compare_inconsistency_notify(s);
706             break;
707         }
708     }
709 }
710 
711 /*
712  * Called from the compare thread on the primary
713  * for compare packet with secondary list of the
714  * specified connection when a new packet was
715  * queued to it.
716  */
717 static void colo_compare_connection(void *opaque, void *user_data)
718 {
719     CompareState *s = user_data;
720     Connection *conn = opaque;
721 
722     switch (conn->ip_proto) {
723     case IPPROTO_TCP:
724         colo_compare_tcp(s, conn);
725         break;
726     case IPPROTO_UDP:
727         colo_compare_packet(s, conn, colo_packet_compare_udp);
728         break;
729     case IPPROTO_ICMP:
730         colo_compare_packet(s, conn, colo_packet_compare_icmp);
731         break;
732     default:
733         colo_compare_packet(s, conn, colo_packet_compare_other);
734         break;
735     }
736 }
737 
738 static void coroutine_fn _compare_chr_send(void *opaque)
739 {
740     SendCo *sendco = opaque;
741     CompareState *s = sendco->s;
742     int ret = 0;
743 
744     while (!g_queue_is_empty(&sendco->send_list)) {
745         SendEntry *entry = g_queue_pop_tail(&sendco->send_list);
746         uint32_t len = htonl(entry->size);
747 
748         ret = qemu_chr_fe_write_all(sendco->chr, (uint8_t *)&len, sizeof(len));
749 
750         if (ret != sizeof(len)) {
751             g_free(entry->buf);
752             g_slice_free(SendEntry, entry);
753             goto err;
754         }
755 
756         if (!sendco->notify_remote_frame && s->vnet_hdr) {
757             /*
758              * We send vnet header len make other module(like filter-redirector)
759              * know how to parse net packet correctly.
760              */
761             len = htonl(entry->vnet_hdr_len);
762 
763             ret = qemu_chr_fe_write_all(sendco->chr,
764                                         (uint8_t *)&len,
765                                         sizeof(len));
766 
767             if (ret != sizeof(len)) {
768                 g_free(entry->buf);
769                 g_slice_free(SendEntry, entry);
770                 goto err;
771             }
772         }
773 
774         ret = qemu_chr_fe_write_all(sendco->chr,
775                                     (uint8_t *)entry->buf,
776                                     entry->size);
777 
778         if (ret != entry->size) {
779             g_free(entry->buf);
780             g_slice_free(SendEntry, entry);
781             goto err;
782         }
783 
784         g_free(entry->buf);
785         g_slice_free(SendEntry, entry);
786     }
787 
788     sendco->ret = 0;
789     goto out;
790 
791 err:
792     while (!g_queue_is_empty(&sendco->send_list)) {
793         SendEntry *entry = g_queue_pop_tail(&sendco->send_list);
794         g_free(entry->buf);
795         g_slice_free(SendEntry, entry);
796     }
797     sendco->ret = ret < 0 ? ret : -EIO;
798 out:
799     sendco->co = NULL;
800     sendco->done = true;
801     aio_wait_kick();
802 }
803 
804 static int compare_chr_send(CompareState *s,
805                             uint8_t *buf,
806                             uint32_t size,
807                             uint32_t vnet_hdr_len,
808                             bool notify_remote_frame,
809                             bool zero_copy)
810 {
811     SendCo *sendco;
812     SendEntry *entry;
813 
814     if (notify_remote_frame) {
815         sendco = &s->notify_sendco;
816     } else {
817         sendco = &s->out_sendco;
818     }
819 
820     if (!size) {
821         return 0;
822     }
823 
824     entry = g_slice_new(SendEntry);
825     entry->size = size;
826     entry->vnet_hdr_len = vnet_hdr_len;
827     if (zero_copy) {
828         entry->buf = buf;
829     } else {
830         entry->buf = g_malloc(size);
831         memcpy(entry->buf, buf, size);
832     }
833     g_queue_push_head(&sendco->send_list, entry);
834 
835     if (sendco->done) {
836         sendco->co = qemu_coroutine_create(_compare_chr_send, sendco);
837         sendco->done = false;
838         qemu_coroutine_enter(sendco->co);
839         if (sendco->done) {
840             /* report early errors */
841             return sendco->ret;
842         }
843     }
844 
845     /* assume success */
846     return 0;
847 }
848 
849 static int compare_chr_can_read(void *opaque)
850 {
851     return COMPARE_READ_LEN_MAX;
852 }
853 
854 /*
855  * Called from the main thread on the primary for packets
856  * arriving over the socket from the primary.
857  */
858 static void compare_pri_chr_in(void *opaque, const uint8_t *buf, int size)
859 {
860     CompareState *s = COLO_COMPARE(opaque);
861     int ret;
862 
863     ret = net_fill_rstate(&s->pri_rs, buf, size);
864     if (ret == -1) {
865         qemu_chr_fe_set_handlers(&s->chr_pri_in, NULL, NULL, NULL, NULL,
866                                  NULL, NULL, true);
867         error_report("colo-compare primary_in error");
868     }
869 }
870 
871 /*
872  * Called from the main thread on the primary for packets
873  * arriving over the socket from the secondary.
874  */
875 static void compare_sec_chr_in(void *opaque, const uint8_t *buf, int size)
876 {
877     CompareState *s = COLO_COMPARE(opaque);
878     int ret;
879 
880     ret = net_fill_rstate(&s->sec_rs, buf, size);
881     if (ret == -1) {
882         qemu_chr_fe_set_handlers(&s->chr_sec_in, NULL, NULL, NULL, NULL,
883                                  NULL, NULL, true);
884         error_report("colo-compare secondary_in error");
885     }
886 }
887 
888 static void compare_notify_chr(void *opaque, const uint8_t *buf, int size)
889 {
890     CompareState *s = COLO_COMPARE(opaque);
891     int ret;
892 
893     ret = net_fill_rstate(&s->notify_rs, buf, size);
894     if (ret == -1) {
895         qemu_chr_fe_set_handlers(&s->chr_notify_dev, NULL, NULL, NULL, NULL,
896                                  NULL, NULL, true);
897         error_report("colo-compare notify_dev error");
898     }
899 }
900 
901 /*
902  * Check old packet regularly so it can watch for any packets
903  * that the secondary hasn't produced equivalents of.
904  */
905 static void check_old_packet_regular(void *opaque)
906 {
907     CompareState *s = opaque;
908 
909     /* if have old packet we will notify checkpoint */
910     colo_old_packet_check(s);
911     timer_mod(s->packet_check_timer, qemu_clock_get_ms(QEMU_CLOCK_HOST) +
912               s->expired_scan_cycle);
913 }
914 
915 /* Public API, Used for COLO frame to notify compare event */
916 void colo_notify_compares_event(void *opaque, int event, Error **errp)
917 {
918     CompareState *s;
919     qemu_mutex_lock(&colo_compare_mutex);
920 
921     if (!colo_compare_active) {
922         qemu_mutex_unlock(&colo_compare_mutex);
923         return;
924     }
925 
926     qemu_mutex_lock(&event_mtx);
927     QTAILQ_FOREACH(s, &net_compares, next) {
928         s->event = event;
929         qemu_bh_schedule(s->event_bh);
930         event_unhandled_count++;
931     }
932     /* Wait all compare threads to finish handling this event */
933     while (event_unhandled_count > 0) {
934         qemu_cond_wait(&event_complete_cond, &event_mtx);
935     }
936 
937     qemu_mutex_unlock(&event_mtx);
938     qemu_mutex_unlock(&colo_compare_mutex);
939 }
940 
941 static void colo_compare_timer_init(CompareState *s)
942 {
943     AioContext *ctx = iothread_get_aio_context(s->iothread);
944 
945     s->packet_check_timer = aio_timer_new(ctx, QEMU_CLOCK_HOST,
946                                 SCALE_MS, check_old_packet_regular,
947                                 s);
948     timer_mod(s->packet_check_timer, qemu_clock_get_ms(QEMU_CLOCK_HOST) +
949               s->expired_scan_cycle);
950 }
951 
952 static void colo_compare_timer_del(CompareState *s)
953 {
954     if (s->packet_check_timer) {
955         timer_free(s->packet_check_timer);
956         s->packet_check_timer = NULL;
957     }
958  }
959 
960 static void colo_flush_packets(void *opaque, void *user_data);
961 
962 static void colo_compare_handle_event(void *opaque)
963 {
964     CompareState *s = opaque;
965 
966     switch (s->event) {
967     case COLO_EVENT_CHECKPOINT:
968         g_queue_foreach(&s->conn_list, colo_flush_packets, s);
969         break;
970     case COLO_EVENT_FAILOVER:
971         break;
972     default:
973         break;
974     }
975 
976     qemu_mutex_lock(&event_mtx);
977     assert(event_unhandled_count > 0);
978     event_unhandled_count--;
979     qemu_cond_broadcast(&event_complete_cond);
980     qemu_mutex_unlock(&event_mtx);
981 }
982 
983 static void colo_compare_iothread(CompareState *s)
984 {
985     AioContext *ctx = iothread_get_aio_context(s->iothread);
986     object_ref(OBJECT(s->iothread));
987     s->worker_context = iothread_get_g_main_context(s->iothread);
988 
989     qemu_chr_fe_set_handlers(&s->chr_pri_in, compare_chr_can_read,
990                              compare_pri_chr_in, NULL, NULL,
991                              s, s->worker_context, true);
992     qemu_chr_fe_set_handlers(&s->chr_sec_in, compare_chr_can_read,
993                              compare_sec_chr_in, NULL, NULL,
994                              s, s->worker_context, true);
995     if (s->notify_dev) {
996         qemu_chr_fe_set_handlers(&s->chr_notify_dev, compare_chr_can_read,
997                                  compare_notify_chr, NULL, NULL,
998                                  s, s->worker_context, true);
999     }
1000 
1001     colo_compare_timer_init(s);
1002     s->event_bh = aio_bh_new(ctx, colo_compare_handle_event, s);
1003 }
1004 
1005 static char *compare_get_pri_indev(Object *obj, Error **errp)
1006 {
1007     CompareState *s = COLO_COMPARE(obj);
1008 
1009     return g_strdup(s->pri_indev);
1010 }
1011 
1012 static void compare_set_pri_indev(Object *obj, const char *value, Error **errp)
1013 {
1014     CompareState *s = COLO_COMPARE(obj);
1015 
1016     g_free(s->pri_indev);
1017     s->pri_indev = g_strdup(value);
1018 }
1019 
1020 static char *compare_get_sec_indev(Object *obj, Error **errp)
1021 {
1022     CompareState *s = COLO_COMPARE(obj);
1023 
1024     return g_strdup(s->sec_indev);
1025 }
1026 
1027 static void compare_set_sec_indev(Object *obj, const char *value, Error **errp)
1028 {
1029     CompareState *s = COLO_COMPARE(obj);
1030 
1031     g_free(s->sec_indev);
1032     s->sec_indev = g_strdup(value);
1033 }
1034 
1035 static char *compare_get_outdev(Object *obj, Error **errp)
1036 {
1037     CompareState *s = COLO_COMPARE(obj);
1038 
1039     return g_strdup(s->outdev);
1040 }
1041 
1042 static void compare_set_outdev(Object *obj, const char *value, Error **errp)
1043 {
1044     CompareState *s = COLO_COMPARE(obj);
1045 
1046     g_free(s->outdev);
1047     s->outdev = g_strdup(value);
1048 }
1049 
1050 static bool compare_get_vnet_hdr(Object *obj, Error **errp)
1051 {
1052     CompareState *s = COLO_COMPARE(obj);
1053 
1054     return s->vnet_hdr;
1055 }
1056 
1057 static void compare_set_vnet_hdr(Object *obj,
1058                                  bool value,
1059                                  Error **errp)
1060 {
1061     CompareState *s = COLO_COMPARE(obj);
1062 
1063     s->vnet_hdr = value;
1064 }
1065 
1066 static char *compare_get_notify_dev(Object *obj, Error **errp)
1067 {
1068     CompareState *s = COLO_COMPARE(obj);
1069 
1070     return g_strdup(s->notify_dev);
1071 }
1072 
1073 static void compare_set_notify_dev(Object *obj, const char *value, Error **errp)
1074 {
1075     CompareState *s = COLO_COMPARE(obj);
1076 
1077     g_free(s->notify_dev);
1078     s->notify_dev = g_strdup(value);
1079 }
1080 
1081 static void compare_get_timeout(Object *obj, Visitor *v,
1082                                 const char *name, void *opaque,
1083                                 Error **errp)
1084 {
1085     CompareState *s = COLO_COMPARE(obj);
1086     uint64_t value = s->compare_timeout;
1087 
1088     visit_type_uint64(v, name, &value, errp);
1089 }
1090 
1091 static void compare_set_timeout(Object *obj, Visitor *v,
1092                                 const char *name, void *opaque,
1093                                 Error **errp)
1094 {
1095     CompareState *s = COLO_COMPARE(obj);
1096     uint32_t value;
1097 
1098     if (!visit_type_uint32(v, name, &value, errp)) {
1099         return;
1100     }
1101     if (!value) {
1102         error_setg(errp, "Property '%s.%s' requires a positive value",
1103                    object_get_typename(obj), name);
1104         return;
1105     }
1106     s->compare_timeout = value;
1107 }
1108 
1109 static void compare_get_expired_scan_cycle(Object *obj, Visitor *v,
1110                                            const char *name, void *opaque,
1111                                            Error **errp)
1112 {
1113     CompareState *s = COLO_COMPARE(obj);
1114     uint32_t value = s->expired_scan_cycle;
1115 
1116     visit_type_uint32(v, name, &value, errp);
1117 }
1118 
1119 static void compare_set_expired_scan_cycle(Object *obj, Visitor *v,
1120                                            const char *name, void *opaque,
1121                                            Error **errp)
1122 {
1123     CompareState *s = COLO_COMPARE(obj);
1124     uint32_t value;
1125 
1126     if (!visit_type_uint32(v, name, &value, errp)) {
1127         return;
1128     }
1129     if (!value) {
1130         error_setg(errp, "Property '%s.%s' requires a positive value",
1131                    object_get_typename(obj), name);
1132         return;
1133     }
1134     s->expired_scan_cycle = value;
1135 }
1136 
1137 static void get_max_queue_size(Object *obj, Visitor *v,
1138                                const char *name, void *opaque,
1139                                Error **errp)
1140 {
1141     uint32_t value = max_queue_size;
1142 
1143     visit_type_uint32(v, name, &value, errp);
1144 }
1145 
1146 static void set_max_queue_size(Object *obj, Visitor *v,
1147                                const char *name, void *opaque,
1148                                Error **errp)
1149 {
1150     Error *local_err = NULL;
1151     uint64_t value;
1152 
1153     visit_type_uint64(v, name, &value, &local_err);
1154     if (local_err) {
1155         goto out;
1156     }
1157     if (!value) {
1158         error_setg(&local_err, "Property '%s.%s' requires a positive value",
1159                    object_get_typename(obj), name);
1160         goto out;
1161     }
1162     max_queue_size = value;
1163 
1164 out:
1165     error_propagate(errp, local_err);
1166 }
1167 
1168 static void compare_pri_rs_finalize(SocketReadState *pri_rs)
1169 {
1170     CompareState *s = container_of(pri_rs, CompareState, pri_rs);
1171     Connection *conn = NULL;
1172 
1173     if (packet_enqueue(s, PRIMARY_IN, &conn)) {
1174         trace_colo_compare_main("primary: unsupported packet in");
1175         compare_chr_send(s,
1176                          pri_rs->buf,
1177                          pri_rs->packet_len,
1178                          pri_rs->vnet_hdr_len,
1179                          false,
1180                          false);
1181     } else {
1182         /* compare packet in the specified connection */
1183         colo_compare_connection(conn, s);
1184     }
1185 }
1186 
1187 static void compare_sec_rs_finalize(SocketReadState *sec_rs)
1188 {
1189     CompareState *s = container_of(sec_rs, CompareState, sec_rs);
1190     Connection *conn = NULL;
1191 
1192     if (packet_enqueue(s, SECONDARY_IN, &conn)) {
1193         trace_colo_compare_main("secondary: unsupported packet in");
1194     } else {
1195         /* compare packet in the specified connection */
1196         colo_compare_connection(conn, s);
1197     }
1198 }
1199 
1200 static void compare_notify_rs_finalize(SocketReadState *notify_rs)
1201 {
1202     CompareState *s = container_of(notify_rs, CompareState, notify_rs);
1203 
1204     const char msg[] = "COLO_COMPARE_GET_XEN_INIT";
1205     int ret;
1206 
1207     if (packet_matches_str("COLO_USERSPACE_PROXY_INIT",
1208                            notify_rs->buf,
1209                            notify_rs->packet_len)) {
1210         ret = compare_chr_send(s, (uint8_t *)msg, strlen(msg), 0, true, false);
1211         if (ret < 0) {
1212             error_report("Notify Xen COLO-frame INIT failed");
1213         }
1214     } else if (packet_matches_str("COLO_CHECKPOINT",
1215                                   notify_rs->buf,
1216                                   notify_rs->packet_len)) {
1217         /* colo-compare do checkpoint, flush pri packet and remove sec packet */
1218         g_queue_foreach(&s->conn_list, colo_flush_packets, s);
1219     } else {
1220         error_report("COLO compare got unsupported instruction");
1221     }
1222 }
1223 
1224 /*
1225  * Return 0 is success.
1226  * Return 1 is failed.
1227  */
1228 static int find_and_check_chardev(Chardev **chr,
1229                                   char *chr_name,
1230                                   Error **errp)
1231 {
1232     *chr = qemu_chr_find(chr_name);
1233     if (*chr == NULL) {
1234         error_setg(errp, "Device '%s' not found",
1235                    chr_name);
1236         return 1;
1237     }
1238 
1239     if (!qemu_chr_has_feature(*chr, QEMU_CHAR_FEATURE_RECONNECTABLE)) {
1240         error_setg(errp, "chardev \"%s\" is not reconnectable",
1241                    chr_name);
1242         return 1;
1243     }
1244 
1245     if (!qemu_chr_has_feature(*chr, QEMU_CHAR_FEATURE_GCONTEXT)) {
1246         error_setg(errp, "chardev \"%s\" cannot switch context",
1247                    chr_name);
1248         return 1;
1249     }
1250 
1251     return 0;
1252 }
1253 
1254 /*
1255  * Called from the main thread on the primary
1256  * to setup colo-compare.
1257  */
1258 static void colo_compare_complete(UserCreatable *uc, Error **errp)
1259 {
1260     CompareState *s = COLO_COMPARE(uc);
1261     Chardev *chr;
1262 
1263     if (!s->pri_indev || !s->sec_indev || !s->outdev || !s->iothread) {
1264         error_setg(errp, "colo compare needs 'primary_in' ,"
1265                    "'secondary_in','outdev','iothread' property set");
1266         return;
1267     } else if (!strcmp(s->pri_indev, s->outdev) ||
1268                !strcmp(s->sec_indev, s->outdev) ||
1269                !strcmp(s->pri_indev, s->sec_indev)) {
1270         error_setg(errp, "'indev' and 'outdev' could not be same "
1271                    "for compare module");
1272         return;
1273     }
1274 
1275     if (!s->compare_timeout) {
1276         /* Set default value to 3000 MS */
1277         s->compare_timeout = DEFAULT_TIME_OUT_MS;
1278     }
1279 
1280     if (!s->expired_scan_cycle) {
1281         /* Set default value to 3000 MS */
1282         s->expired_scan_cycle = REGULAR_PACKET_CHECK_MS;
1283     }
1284 
1285     if (!max_queue_size) {
1286         /* Set default queue size to 1024 */
1287         max_queue_size = MAX_QUEUE_SIZE;
1288     }
1289 
1290     if (find_and_check_chardev(&chr, s->pri_indev, errp) ||
1291         !qemu_chr_fe_init(&s->chr_pri_in, chr, errp)) {
1292         return;
1293     }
1294 
1295     if (find_and_check_chardev(&chr, s->sec_indev, errp) ||
1296         !qemu_chr_fe_init(&s->chr_sec_in, chr, errp)) {
1297         return;
1298     }
1299 
1300     if (find_and_check_chardev(&chr, s->outdev, errp) ||
1301         !qemu_chr_fe_init(&s->chr_out, chr, errp)) {
1302         return;
1303     }
1304 
1305     net_socket_rs_init(&s->pri_rs, compare_pri_rs_finalize, s->vnet_hdr);
1306     net_socket_rs_init(&s->sec_rs, compare_sec_rs_finalize, s->vnet_hdr);
1307 
1308     /* Try to enable remote notify chardev, currently just for Xen COLO */
1309     if (s->notify_dev) {
1310         if (find_and_check_chardev(&chr, s->notify_dev, errp) ||
1311             !qemu_chr_fe_init(&s->chr_notify_dev, chr, errp)) {
1312             return;
1313         }
1314 
1315         net_socket_rs_init(&s->notify_rs, compare_notify_rs_finalize,
1316                            s->vnet_hdr);
1317     }
1318 
1319     s->out_sendco.s = s;
1320     s->out_sendco.chr = &s->chr_out;
1321     s->out_sendco.notify_remote_frame = false;
1322     s->out_sendco.done = true;
1323     g_queue_init(&s->out_sendco.send_list);
1324 
1325     if (s->notify_dev) {
1326         s->notify_sendco.s = s;
1327         s->notify_sendco.chr = &s->chr_notify_dev;
1328         s->notify_sendco.notify_remote_frame = true;
1329         s->notify_sendco.done = true;
1330         g_queue_init(&s->notify_sendco.send_list);
1331     }
1332 
1333     g_queue_init(&s->conn_list);
1334 
1335     s->connection_track_table = g_hash_table_new_full(connection_key_hash,
1336                                                       connection_key_equal,
1337                                                       g_free,
1338                                                       connection_destroy);
1339 
1340     colo_compare_iothread(s);
1341 
1342     qemu_mutex_lock(&colo_compare_mutex);
1343     if (!colo_compare_active) {
1344         qemu_mutex_init(&event_mtx);
1345         qemu_cond_init(&event_complete_cond);
1346         colo_compare_active = true;
1347     }
1348     QTAILQ_INSERT_TAIL(&net_compares, s, next);
1349     qemu_mutex_unlock(&colo_compare_mutex);
1350 
1351     return;
1352 }
1353 
1354 static void colo_flush_packets(void *opaque, void *user_data)
1355 {
1356     CompareState *s = user_data;
1357     Connection *conn = opaque;
1358     Packet *pkt = NULL;
1359 
1360     while (!g_queue_is_empty(&conn->primary_list)) {
1361         pkt = g_queue_pop_head(&conn->primary_list);
1362         compare_chr_send(s,
1363                          pkt->data,
1364                          pkt->size,
1365                          pkt->vnet_hdr_len,
1366                          false,
1367                          true);
1368         packet_destroy_partial(pkt, NULL);
1369     }
1370     while (!g_queue_is_empty(&conn->secondary_list)) {
1371         pkt = g_queue_pop_head(&conn->secondary_list);
1372         packet_destroy(pkt, NULL);
1373     }
1374 }
1375 
1376 static void colo_compare_class_init(ObjectClass *oc, void *data)
1377 {
1378     UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
1379 
1380     ucc->complete = colo_compare_complete;
1381 }
1382 
1383 static void colo_compare_init(Object *obj)
1384 {
1385     CompareState *s = COLO_COMPARE(obj);
1386 
1387     object_property_add_str(obj, "primary_in",
1388                             compare_get_pri_indev, compare_set_pri_indev);
1389     object_property_add_str(obj, "secondary_in",
1390                             compare_get_sec_indev, compare_set_sec_indev);
1391     object_property_add_str(obj, "outdev",
1392                             compare_get_outdev, compare_set_outdev);
1393     object_property_add_link(obj, "iothread", TYPE_IOTHREAD,
1394                             (Object **)&s->iothread,
1395                             object_property_allow_set_link,
1396                             OBJ_PROP_LINK_STRONG);
1397     /* This parameter just for Xen COLO */
1398     object_property_add_str(obj, "notify_dev",
1399                             compare_get_notify_dev, compare_set_notify_dev);
1400 
1401     object_property_add(obj, "compare_timeout", "uint64",
1402                         compare_get_timeout,
1403                         compare_set_timeout, NULL, NULL);
1404 
1405     object_property_add(obj, "expired_scan_cycle", "uint32",
1406                         compare_get_expired_scan_cycle,
1407                         compare_set_expired_scan_cycle, NULL, NULL);
1408 
1409     object_property_add(obj, "max_queue_size", "uint32",
1410                         get_max_queue_size,
1411                         set_max_queue_size, NULL, NULL);
1412 
1413     s->vnet_hdr = false;
1414     object_property_add_bool(obj, "vnet_hdr_support", compare_get_vnet_hdr,
1415                              compare_set_vnet_hdr);
1416 }
1417 
1418 static void colo_compare_finalize(Object *obj)
1419 {
1420     CompareState *s = COLO_COMPARE(obj);
1421     CompareState *tmp = NULL;
1422 
1423     qemu_mutex_lock(&colo_compare_mutex);
1424     QTAILQ_FOREACH(tmp, &net_compares, next) {
1425         if (tmp == s) {
1426             QTAILQ_REMOVE(&net_compares, s, next);
1427             break;
1428         }
1429     }
1430     if (QTAILQ_EMPTY(&net_compares)) {
1431         colo_compare_active = false;
1432         qemu_mutex_destroy(&event_mtx);
1433         qemu_cond_destroy(&event_complete_cond);
1434     }
1435     qemu_mutex_unlock(&colo_compare_mutex);
1436 
1437     qemu_chr_fe_deinit(&s->chr_pri_in, false);
1438     qemu_chr_fe_deinit(&s->chr_sec_in, false);
1439     qemu_chr_fe_deinit(&s->chr_out, false);
1440     if (s->notify_dev) {
1441         qemu_chr_fe_deinit(&s->chr_notify_dev, false);
1442     }
1443 
1444     colo_compare_timer_del(s);
1445 
1446     qemu_bh_delete(s->event_bh);
1447 
1448     AioContext *ctx = iothread_get_aio_context(s->iothread);
1449     aio_context_acquire(ctx);
1450     AIO_WAIT_WHILE(ctx, !s->out_sendco.done);
1451     if (s->notify_dev) {
1452         AIO_WAIT_WHILE(ctx, !s->notify_sendco.done);
1453     }
1454     aio_context_release(ctx);
1455 
1456     /* Release all unhandled packets after compare thead exited */
1457     g_queue_foreach(&s->conn_list, colo_flush_packets, s);
1458     AIO_WAIT_WHILE(NULL, !s->out_sendco.done);
1459 
1460     g_queue_clear(&s->conn_list);
1461     g_queue_clear(&s->out_sendco.send_list);
1462     if (s->notify_dev) {
1463         g_queue_clear(&s->notify_sendco.send_list);
1464     }
1465 
1466     if (s->connection_track_table) {
1467         g_hash_table_destroy(s->connection_track_table);
1468     }
1469 
1470     object_unref(OBJECT(s->iothread));
1471 
1472     g_free(s->pri_indev);
1473     g_free(s->sec_indev);
1474     g_free(s->outdev);
1475     g_free(s->notify_dev);
1476 }
1477 
1478 static void __attribute__((__constructor__)) colo_compare_init_globals(void)
1479 {
1480     colo_compare_active = false;
1481     qemu_mutex_init(&colo_compare_mutex);
1482 }
1483 
1484 static const TypeInfo colo_compare_info = {
1485     .name = TYPE_COLO_COMPARE,
1486     .parent = TYPE_OBJECT,
1487     .instance_size = sizeof(CompareState),
1488     .instance_init = colo_compare_init,
1489     .instance_finalize = colo_compare_finalize,
1490     .class_size = sizeof(CompareClass),
1491     .class_init = colo_compare_class_init,
1492     .interfaces = (InterfaceInfo[]) {
1493         { TYPE_USER_CREATABLE },
1494         { }
1495     }
1496 };
1497 
1498 static void register_types(void)
1499 {
1500     type_register_static(&colo_compare_info);
1501 }
1502 
1503 type_init(register_types);
1504