xref: /openbmc/qemu/net/colo-compare.c (revision d40d3da0)
1 /*
2  * COarse-grain LOck-stepping Virtual Machines for Non-stop Service (COLO)
3  * (a.k.a. Fault Tolerance or Continuous Replication)
4  *
5  * Copyright (c) 2016 HUAWEI TECHNOLOGIES CO., LTD.
6  * Copyright (c) 2016 FUJITSU LIMITED
7  * Copyright (c) 2016 Intel Corporation
8  *
9  * Author: Zhang Chen <zhangchen.fnst@cn.fujitsu.com>
10  *
11  * This work is licensed under the terms of the GNU GPL, version 2 or
12  * later.  See the COPYING file in the top-level directory.
13  */
14 
15 #include "qemu/osdep.h"
16 #include "qemu/error-report.h"
17 #include "trace.h"
18 #include "qemu-common.h"
19 #include "qapi/qmp/qerror.h"
20 #include "qapi/error.h"
21 #include "net/net.h"
22 #include "net/eth.h"
23 #include "qom/object_interfaces.h"
24 #include "qemu/iov.h"
25 #include "qom/object.h"
26 #include "qemu/typedefs.h"
27 #include "net/queue.h"
28 #include "chardev/char-fe.h"
29 #include "qemu/sockets.h"
30 #include "qapi-visit.h"
31 #include "net/colo.h"
32 
33 #define TYPE_COLO_COMPARE "colo-compare"
34 #define COLO_COMPARE(obj) \
35     OBJECT_CHECK(CompareState, (obj), TYPE_COLO_COMPARE)
36 
37 #define COMPARE_READ_LEN_MAX NET_BUFSIZE
38 #define MAX_QUEUE_SIZE 1024
39 
40 /* TODO: Should be configurable */
41 #define REGULAR_PACKET_CHECK_MS 3000
42 
43 /*
44   + CompareState ++
45   |               |
46   +---------------+   +---------------+         +---------------+
47   |conn list      +--->conn           +--------->conn           |
48   +---------------+   +---------------+         +---------------+
49   |               |     |           |             |          |
50   +---------------+ +---v----+  +---v----+    +---v----+ +---v----+
51                     |primary |  |secondary    |primary | |secondary
52                     |packet  |  |packet  +    |packet  | |packet  +
53                     +--------+  +--------+    +--------+ +--------+
54                         |           |             |          |
55                     +---v----+  +---v----+    +---v----+ +---v----+
56                     |primary |  |secondary    |primary | |secondary
57                     |packet  |  |packet  +    |packet  | |packet  +
58                     +--------+  +--------+    +--------+ +--------+
59                         |           |             |          |
60                     +---v----+  +---v----+    +---v----+ +---v----+
61                     |primary |  |secondary    |primary | |secondary
62                     |packet  |  |packet  +    |packet  | |packet  +
63                     +--------+  +--------+    +--------+ +--------+
64 */
65 typedef struct CompareState {
66     Object parent;
67 
68     char *pri_indev;
69     char *sec_indev;
70     char *outdev;
71     CharBackend chr_pri_in;
72     CharBackend chr_sec_in;
73     CharBackend chr_out;
74     SocketReadState pri_rs;
75     SocketReadState sec_rs;
76 
77     /* connection list: the connections belonged to this NIC could be found
78      * in this list.
79      * element type: Connection
80      */
81     GQueue conn_list;
82     /* hashtable to save connection */
83     GHashTable *connection_track_table;
84     /* compare thread, a thread for each NIC */
85     QemuThread thread;
86 
87     GMainContext *worker_context;
88     GMainLoop *compare_loop;
89 } CompareState;
90 
91 typedef struct CompareClass {
92     ObjectClass parent_class;
93 } CompareClass;
94 
95 enum {
96     PRIMARY_IN = 0,
97     SECONDARY_IN,
98 };
99 
100 static int compare_chr_send(CharBackend *out,
101                             const uint8_t *buf,
102                             uint32_t size);
103 
104 static gint seq_sorter(Packet *a, Packet *b, gpointer data)
105 {
106     struct tcphdr *atcp, *btcp;
107 
108     atcp = (struct tcphdr *)(a->transport_header);
109     btcp = (struct tcphdr *)(b->transport_header);
110     return ntohl(atcp->th_seq) - ntohl(btcp->th_seq);
111 }
112 
113 /*
114  * Return 0 on success, if return -1 means the pkt
115  * is unsupported(arp and ipv6) and will be sent later
116  */
117 static int packet_enqueue(CompareState *s, int mode)
118 {
119     ConnectionKey key;
120     Packet *pkt = NULL;
121     Connection *conn;
122 
123     if (mode == PRIMARY_IN) {
124         pkt = packet_new(s->pri_rs.buf, s->pri_rs.packet_len);
125     } else {
126         pkt = packet_new(s->sec_rs.buf, s->sec_rs.packet_len);
127     }
128 
129     if (parse_packet_early(pkt)) {
130         packet_destroy(pkt, NULL);
131         pkt = NULL;
132         return -1;
133     }
134     fill_connection_key(pkt, &key);
135 
136     conn = connection_get(s->connection_track_table,
137                           &key,
138                           &s->conn_list);
139 
140     if (!conn->processing) {
141         g_queue_push_tail(&s->conn_list, conn);
142         conn->processing = true;
143     }
144 
145     if (mode == PRIMARY_IN) {
146         if (g_queue_get_length(&conn->primary_list) <=
147                                MAX_QUEUE_SIZE) {
148             g_queue_push_tail(&conn->primary_list, pkt);
149             if (conn->ip_proto == IPPROTO_TCP) {
150                 g_queue_sort(&conn->primary_list,
151                              (GCompareDataFunc)seq_sorter,
152                              NULL);
153             }
154         } else {
155             error_report("colo compare primary queue size too big,"
156                          "drop packet");
157         }
158     } else {
159         if (g_queue_get_length(&conn->secondary_list) <=
160                                MAX_QUEUE_SIZE) {
161             g_queue_push_tail(&conn->secondary_list, pkt);
162             if (conn->ip_proto == IPPROTO_TCP) {
163                 g_queue_sort(&conn->secondary_list,
164                              (GCompareDataFunc)seq_sorter,
165                              NULL);
166             }
167         } else {
168             error_report("colo compare secondary queue size too big,"
169                          "drop packet");
170         }
171     }
172 
173     return 0;
174 }
175 
176 /*
177  * The IP packets sent by primary and secondary
178  * will be compared in here
179  * TODO support ip fragment, Out-Of-Order
180  * return:    0  means packet same
181  *            > 0 || < 0 means packet different
182  */
183 static int colo_packet_compare_common(Packet *ppkt, Packet *spkt, int offset)
184 {
185     if (trace_event_get_state(TRACE_COLO_COMPARE_MISCOMPARE)) {
186         char pri_ip_src[20], pri_ip_dst[20], sec_ip_src[20], sec_ip_dst[20];
187 
188         strcpy(pri_ip_src, inet_ntoa(ppkt->ip->ip_src));
189         strcpy(pri_ip_dst, inet_ntoa(ppkt->ip->ip_dst));
190         strcpy(sec_ip_src, inet_ntoa(spkt->ip->ip_src));
191         strcpy(sec_ip_dst, inet_ntoa(spkt->ip->ip_dst));
192 
193         trace_colo_compare_ip_info(ppkt->size, pri_ip_src,
194                                    pri_ip_dst, spkt->size,
195                                    sec_ip_src, sec_ip_dst);
196     }
197 
198     if (ppkt->size == spkt->size) {
199         return memcmp(ppkt->data + offset, spkt->data + offset,
200                       spkt->size - offset);
201     } else {
202         trace_colo_compare_main("Net packet size are not the same");
203         return -1;
204     }
205 }
206 
207 /*
208  * Called from the compare thread on the primary
209  * for compare tcp packet
210  * compare_tcp copied from Dr. David Alan Gilbert's branch
211  */
212 static int colo_packet_compare_tcp(Packet *spkt, Packet *ppkt)
213 {
214     struct tcphdr *ptcp, *stcp;
215     int res;
216 
217     trace_colo_compare_main("compare tcp");
218 
219     ptcp = (struct tcphdr *)ppkt->transport_header;
220     stcp = (struct tcphdr *)spkt->transport_header;
221 
222     /*
223      * The 'identification' field in the IP header is *very* random
224      * it almost never matches.  Fudge this by ignoring differences in
225      * unfragmented packets; they'll normally sort themselves out if different
226      * anyway, and it should recover at the TCP level.
227      * An alternative would be to get both the primary and secondary to rewrite
228      * somehow; but that would need some sync traffic to sync the state
229      */
230     if (ntohs(ppkt->ip->ip_off) & IP_DF) {
231         spkt->ip->ip_id = ppkt->ip->ip_id;
232         /* and the sum will be different if the IDs were different */
233         spkt->ip->ip_sum = ppkt->ip->ip_sum;
234     }
235 
236     /*
237      * Check tcp header length for tcp option field.
238      * th_off > 5 means this tcp packet have options field.
239      * The tcp options maybe always different.
240      * for example:
241      * From RFC 7323.
242      * TCP Timestamps option (TSopt):
243      * Kind: 8
244      *
245      * Length: 10 bytes
246      *
247      *    +-------+-------+---------------------+---------------------+
248      *    |Kind=8 |  10   |   TS Value (TSval)  |TS Echo Reply (TSecr)|
249      *    +-------+-------+---------------------+---------------------+
250      *       1       1              4                     4
251      *
252      * In this case the primary guest's timestamp always different with
253      * the secondary guest's timestamp. COLO just focus on payload,
254      * so we just need skip this field.
255      */
256     if (ptcp->th_off > 5) {
257         ptrdiff_t tcp_offset;
258         tcp_offset = ppkt->transport_header - (uint8_t *)ppkt->data
259                      + (ptcp->th_off * 4);
260         res = colo_packet_compare_common(ppkt, spkt, tcp_offset);
261     } else if (ptcp->th_sum == stcp->th_sum) {
262         res = colo_packet_compare_common(ppkt, spkt, ETH_HLEN);
263     } else {
264         res = -1;
265     }
266 
267     if (res != 0 && trace_event_get_state(TRACE_COLO_COMPARE_MISCOMPARE)) {
268         char pri_ip_src[20], pri_ip_dst[20], sec_ip_src[20], sec_ip_dst[20];
269 
270         strcpy(pri_ip_src, inet_ntoa(ppkt->ip->ip_src));
271         strcpy(pri_ip_dst, inet_ntoa(ppkt->ip->ip_dst));
272         strcpy(sec_ip_src, inet_ntoa(spkt->ip->ip_src));
273         strcpy(sec_ip_dst, inet_ntoa(spkt->ip->ip_dst));
274 
275         trace_colo_compare_ip_info(ppkt->size, pri_ip_src,
276                                    pri_ip_dst, spkt->size,
277                                    sec_ip_src, sec_ip_dst);
278 
279         trace_colo_compare_tcp_info("pri tcp packet",
280                                     ntohl(ptcp->th_seq),
281                                     ntohl(ptcp->th_ack),
282                                     res, ptcp->th_flags,
283                                     ppkt->size);
284 
285         trace_colo_compare_tcp_info("sec tcp packet",
286                                     ntohl(stcp->th_seq),
287                                     ntohl(stcp->th_ack),
288                                     res, stcp->th_flags,
289                                     spkt->size);
290 
291         qemu_hexdump((char *)ppkt->data, stderr,
292                      "colo-compare ppkt", ppkt->size);
293         qemu_hexdump((char *)spkt->data, stderr,
294                      "colo-compare spkt", spkt->size);
295     }
296 
297     return res;
298 }
299 
300 /*
301  * Called from the compare thread on the primary
302  * for compare udp packet
303  */
304 static int colo_packet_compare_udp(Packet *spkt, Packet *ppkt)
305 {
306     int ret;
307     int network_header_length = ppkt->ip->ip_hl * 4;
308 
309     trace_colo_compare_main("compare udp");
310 
311     /*
312      * Because of ppkt and spkt are both in the same connection,
313      * The ppkt's src ip, dst ip, src port, dst port, ip_proto all are
314      * same with spkt. In addition, IP header's Identification is a random
315      * field, we can handle it in IP fragmentation function later.
316      * COLO just concern the response net packet payload from primary guest
317      * and secondary guest are same or not, So we ignored all IP header include
318      * other field like TOS,TTL,IP Checksum. we only need to compare
319      * the ip payload here.
320      */
321     ret = colo_packet_compare_common(ppkt, spkt,
322                                      network_header_length + ETH_HLEN);
323 
324     if (ret) {
325         trace_colo_compare_udp_miscompare("primary pkt size", ppkt->size);
326         trace_colo_compare_udp_miscompare("Secondary pkt size", spkt->size);
327         if (trace_event_get_state(TRACE_COLO_COMPARE_MISCOMPARE)) {
328             qemu_hexdump((char *)ppkt->data, stderr, "colo-compare pri pkt",
329                          ppkt->size);
330             qemu_hexdump((char *)spkt->data, stderr, "colo-compare sec pkt",
331                          spkt->size);
332         }
333     }
334 
335     return ret;
336 }
337 
338 /*
339  * Called from the compare thread on the primary
340  * for compare icmp packet
341  */
342 static int colo_packet_compare_icmp(Packet *spkt, Packet *ppkt)
343 {
344     int network_header_length = ppkt->ip->ip_hl * 4;
345 
346     trace_colo_compare_main("compare icmp");
347 
348     /*
349      * Because of ppkt and spkt are both in the same connection,
350      * The ppkt's src ip, dst ip, src port, dst port, ip_proto all are
351      * same with spkt. In addition, IP header's Identification is a random
352      * field, we can handle it in IP fragmentation function later.
353      * COLO just concern the response net packet payload from primary guest
354      * and secondary guest are same or not, So we ignored all IP header include
355      * other field like TOS,TTL,IP Checksum. we only need to compare
356      * the ip payload here.
357      */
358     if (colo_packet_compare_common(ppkt, spkt,
359                                    network_header_length + ETH_HLEN)) {
360         trace_colo_compare_icmp_miscompare("primary pkt size",
361                                            ppkt->size);
362         trace_colo_compare_icmp_miscompare("Secondary pkt size",
363                                            spkt->size);
364         if (trace_event_get_state(TRACE_COLO_COMPARE_MISCOMPARE)) {
365             qemu_hexdump((char *)ppkt->data, stderr, "colo-compare pri pkt",
366                          ppkt->size);
367             qemu_hexdump((char *)spkt->data, stderr, "colo-compare sec pkt",
368                          spkt->size);
369         }
370         return -1;
371     } else {
372         return 0;
373     }
374 }
375 
376 /*
377  * Called from the compare thread on the primary
378  * for compare other packet
379  */
380 static int colo_packet_compare_other(Packet *spkt, Packet *ppkt)
381 {
382     trace_colo_compare_main("compare other");
383     if (trace_event_get_state(TRACE_COLO_COMPARE_MISCOMPARE)) {
384         char pri_ip_src[20], pri_ip_dst[20], sec_ip_src[20], sec_ip_dst[20];
385 
386         strcpy(pri_ip_src, inet_ntoa(ppkt->ip->ip_src));
387         strcpy(pri_ip_dst, inet_ntoa(ppkt->ip->ip_dst));
388         strcpy(sec_ip_src, inet_ntoa(spkt->ip->ip_src));
389         strcpy(sec_ip_dst, inet_ntoa(spkt->ip->ip_dst));
390 
391         trace_colo_compare_ip_info(ppkt->size, pri_ip_src,
392                                    pri_ip_dst, spkt->size,
393                                    sec_ip_src, sec_ip_dst);
394     }
395 
396     return colo_packet_compare_common(ppkt, spkt, 0);
397 }
398 
399 static int colo_old_packet_check_one(Packet *pkt, int64_t *check_time)
400 {
401     int64_t now = qemu_clock_get_ms(QEMU_CLOCK_HOST);
402 
403     if ((now - pkt->creation_ms) > (*check_time)) {
404         trace_colo_old_packet_check_found(pkt->creation_ms);
405         return 0;
406     } else {
407         return 1;
408     }
409 }
410 
411 static int colo_old_packet_check_one_conn(Connection *conn,
412                                           void *user_data)
413 {
414     GList *result = NULL;
415     int64_t check_time = REGULAR_PACKET_CHECK_MS;
416 
417     result = g_queue_find_custom(&conn->primary_list,
418                                  &check_time,
419                                  (GCompareFunc)colo_old_packet_check_one);
420 
421     if (result) {
422         /* do checkpoint will flush old packet */
423         /* TODO: colo_notify_checkpoint();*/
424         return 0;
425     }
426 
427     return 1;
428 }
429 
430 /*
431  * Look for old packets that the secondary hasn't matched,
432  * if we have some then we have to checkpoint to wake
433  * the secondary up.
434  */
435 static void colo_old_packet_check(void *opaque)
436 {
437     CompareState *s = opaque;
438 
439     /*
440      * If we find one old packet, stop finding job and notify
441      * COLO frame do checkpoint.
442      */
443     g_queue_find_custom(&s->conn_list, NULL,
444                         (GCompareFunc)colo_old_packet_check_one_conn);
445 }
446 
447 /*
448  * Called from the compare thread on the primary
449  * for compare connection
450  */
451 static void colo_compare_connection(void *opaque, void *user_data)
452 {
453     CompareState *s = user_data;
454     Connection *conn = opaque;
455     Packet *pkt = NULL;
456     GList *result = NULL;
457     int ret;
458 
459     while (!g_queue_is_empty(&conn->primary_list) &&
460            !g_queue_is_empty(&conn->secondary_list)) {
461         pkt = g_queue_pop_tail(&conn->primary_list);
462         switch (conn->ip_proto) {
463         case IPPROTO_TCP:
464             result = g_queue_find_custom(&conn->secondary_list,
465                      pkt, (GCompareFunc)colo_packet_compare_tcp);
466             break;
467         case IPPROTO_UDP:
468             result = g_queue_find_custom(&conn->secondary_list,
469                      pkt, (GCompareFunc)colo_packet_compare_udp);
470             break;
471         case IPPROTO_ICMP:
472             result = g_queue_find_custom(&conn->secondary_list,
473                      pkt, (GCompareFunc)colo_packet_compare_icmp);
474             break;
475         default:
476             result = g_queue_find_custom(&conn->secondary_list,
477                      pkt, (GCompareFunc)colo_packet_compare_other);
478             break;
479         }
480 
481         if (result) {
482             ret = compare_chr_send(&s->chr_out, pkt->data, pkt->size);
483             if (ret < 0) {
484                 error_report("colo_send_primary_packet failed");
485             }
486             trace_colo_compare_main("packet same and release packet");
487             g_queue_remove(&conn->secondary_list, result->data);
488             packet_destroy(pkt, NULL);
489         } else {
490             /*
491              * If one packet arrive late, the secondary_list or
492              * primary_list will be empty, so we can't compare it
493              * until next comparison.
494              */
495             trace_colo_compare_main("packet different");
496             g_queue_push_tail(&conn->primary_list, pkt);
497             /* TODO: colo_notify_checkpoint();*/
498             break;
499         }
500     }
501 }
502 
503 static int compare_chr_send(CharBackend *out,
504                             const uint8_t *buf,
505                             uint32_t size)
506 {
507     int ret = 0;
508     uint32_t len = htonl(size);
509 
510     if (!size) {
511         return 0;
512     }
513 
514     ret = qemu_chr_fe_write_all(out, (uint8_t *)&len, sizeof(len));
515     if (ret != sizeof(len)) {
516         goto err;
517     }
518 
519     ret = qemu_chr_fe_write_all(out, (uint8_t *)buf, size);
520     if (ret != size) {
521         goto err;
522     }
523 
524     return 0;
525 
526 err:
527     return ret < 0 ? ret : -EIO;
528 }
529 
530 static int compare_chr_can_read(void *opaque)
531 {
532     return COMPARE_READ_LEN_MAX;
533 }
534 
535 /*
536  * Called from the main thread on the primary for packets
537  * arriving over the socket from the primary.
538  */
539 static void compare_pri_chr_in(void *opaque, const uint8_t *buf, int size)
540 {
541     CompareState *s = COLO_COMPARE(opaque);
542     int ret;
543 
544     ret = net_fill_rstate(&s->pri_rs, buf, size);
545     if (ret == -1) {
546         qemu_chr_fe_set_handlers(&s->chr_pri_in, NULL, NULL, NULL, NULL,
547                                  NULL, NULL, true);
548         error_report("colo-compare primary_in error");
549     }
550 }
551 
552 /*
553  * Called from the main thread on the primary for packets
554  * arriving over the socket from the secondary.
555  */
556 static void compare_sec_chr_in(void *opaque, const uint8_t *buf, int size)
557 {
558     CompareState *s = COLO_COMPARE(opaque);
559     int ret;
560 
561     ret = net_fill_rstate(&s->sec_rs, buf, size);
562     if (ret == -1) {
563         qemu_chr_fe_set_handlers(&s->chr_sec_in, NULL, NULL, NULL, NULL,
564                                  NULL, NULL, true);
565         error_report("colo-compare secondary_in error");
566     }
567 }
568 
569 /*
570  * Check old packet regularly so it can watch for any packets
571  * that the secondary hasn't produced equivalents of.
572  */
573 static gboolean check_old_packet_regular(void *opaque)
574 {
575     CompareState *s = opaque;
576 
577     /* if have old packet we will notify checkpoint */
578     colo_old_packet_check(s);
579 
580     return TRUE;
581 }
582 
583 static void *colo_compare_thread(void *opaque)
584 {
585     CompareState *s = opaque;
586     GSource *timeout_source;
587 
588     s->worker_context = g_main_context_new();
589 
590     qemu_chr_fe_set_handlers(&s->chr_pri_in, compare_chr_can_read,
591                              compare_pri_chr_in, NULL, NULL,
592                              s, s->worker_context, true);
593     qemu_chr_fe_set_handlers(&s->chr_sec_in, compare_chr_can_read,
594                              compare_sec_chr_in, NULL, NULL,
595                              s, s->worker_context, true);
596 
597     s->compare_loop = g_main_loop_new(s->worker_context, FALSE);
598 
599     /* To kick any packets that the secondary doesn't match */
600     timeout_source = g_timeout_source_new(REGULAR_PACKET_CHECK_MS);
601     g_source_set_callback(timeout_source,
602                           (GSourceFunc)check_old_packet_regular, s, NULL);
603     g_source_attach(timeout_source, s->worker_context);
604 
605     g_main_loop_run(s->compare_loop);
606 
607     g_source_unref(timeout_source);
608     g_main_loop_unref(s->compare_loop);
609     g_main_context_unref(s->worker_context);
610     return NULL;
611 }
612 
613 static char *compare_get_pri_indev(Object *obj, Error **errp)
614 {
615     CompareState *s = COLO_COMPARE(obj);
616 
617     return g_strdup(s->pri_indev);
618 }
619 
620 static void compare_set_pri_indev(Object *obj, const char *value, Error **errp)
621 {
622     CompareState *s = COLO_COMPARE(obj);
623 
624     g_free(s->pri_indev);
625     s->pri_indev = g_strdup(value);
626 }
627 
628 static char *compare_get_sec_indev(Object *obj, Error **errp)
629 {
630     CompareState *s = COLO_COMPARE(obj);
631 
632     return g_strdup(s->sec_indev);
633 }
634 
635 static void compare_set_sec_indev(Object *obj, const char *value, Error **errp)
636 {
637     CompareState *s = COLO_COMPARE(obj);
638 
639     g_free(s->sec_indev);
640     s->sec_indev = g_strdup(value);
641 }
642 
643 static char *compare_get_outdev(Object *obj, Error **errp)
644 {
645     CompareState *s = COLO_COMPARE(obj);
646 
647     return g_strdup(s->outdev);
648 }
649 
650 static void compare_set_outdev(Object *obj, const char *value, Error **errp)
651 {
652     CompareState *s = COLO_COMPARE(obj);
653 
654     g_free(s->outdev);
655     s->outdev = g_strdup(value);
656 }
657 
658 static void compare_pri_rs_finalize(SocketReadState *pri_rs)
659 {
660     CompareState *s = container_of(pri_rs, CompareState, pri_rs);
661 
662     if (packet_enqueue(s, PRIMARY_IN)) {
663         trace_colo_compare_main("primary: unsupported packet in");
664         compare_chr_send(&s->chr_out, pri_rs->buf, pri_rs->packet_len);
665     } else {
666         /* compare connection */
667         g_queue_foreach(&s->conn_list, colo_compare_connection, s);
668     }
669 }
670 
671 static void compare_sec_rs_finalize(SocketReadState *sec_rs)
672 {
673     CompareState *s = container_of(sec_rs, CompareState, sec_rs);
674 
675     if (packet_enqueue(s, SECONDARY_IN)) {
676         trace_colo_compare_main("secondary: unsupported packet in");
677     } else {
678         /* compare connection */
679         g_queue_foreach(&s->conn_list, colo_compare_connection, s);
680     }
681 }
682 
683 
684 /*
685  * Return 0 is success.
686  * Return 1 is failed.
687  */
688 static int find_and_check_chardev(Chardev **chr,
689                                   char *chr_name,
690                                   Error **errp)
691 {
692     *chr = qemu_chr_find(chr_name);
693     if (*chr == NULL) {
694         error_setg(errp, "Device '%s' not found",
695                    chr_name);
696         return 1;
697     }
698 
699     if (!qemu_chr_has_feature(*chr, QEMU_CHAR_FEATURE_RECONNECTABLE)) {
700         error_setg(errp, "chardev \"%s\" is not reconnectable",
701                    chr_name);
702         return 1;
703     }
704 
705     return 0;
706 }
707 
708 /*
709  * Called from the main thread on the primary
710  * to setup colo-compare.
711  */
712 static void colo_compare_complete(UserCreatable *uc, Error **errp)
713 {
714     CompareState *s = COLO_COMPARE(uc);
715     Chardev *chr;
716     char thread_name[64];
717     static int compare_id;
718 
719     if (!s->pri_indev || !s->sec_indev || !s->outdev) {
720         error_setg(errp, "colo compare needs 'primary_in' ,"
721                    "'secondary_in','outdev' property set");
722         return;
723     } else if (!strcmp(s->pri_indev, s->outdev) ||
724                !strcmp(s->sec_indev, s->outdev) ||
725                !strcmp(s->pri_indev, s->sec_indev)) {
726         error_setg(errp, "'indev' and 'outdev' could not be same "
727                    "for compare module");
728         return;
729     }
730 
731     if (find_and_check_chardev(&chr, s->pri_indev, errp) ||
732         !qemu_chr_fe_init(&s->chr_pri_in, chr, errp)) {
733         return;
734     }
735 
736     if (find_and_check_chardev(&chr, s->sec_indev, errp) ||
737         !qemu_chr_fe_init(&s->chr_sec_in, chr, errp)) {
738         return;
739     }
740 
741     if (find_and_check_chardev(&chr, s->outdev, errp) ||
742         !qemu_chr_fe_init(&s->chr_out, chr, errp)) {
743         return;
744     }
745 
746     net_socket_rs_init(&s->pri_rs, compare_pri_rs_finalize);
747     net_socket_rs_init(&s->sec_rs, compare_sec_rs_finalize);
748 
749     g_queue_init(&s->conn_list);
750 
751     s->connection_track_table = g_hash_table_new_full(connection_key_hash,
752                                                       connection_key_equal,
753                                                       g_free,
754                                                       connection_destroy);
755 
756     sprintf(thread_name, "colo-compare %d", compare_id);
757     qemu_thread_create(&s->thread, thread_name,
758                        colo_compare_thread, s,
759                        QEMU_THREAD_JOINABLE);
760     compare_id++;
761 
762     return;
763 }
764 
765 static void colo_flush_packets(void *opaque, void *user_data)
766 {
767     CompareState *s = user_data;
768     Connection *conn = opaque;
769     Packet *pkt = NULL;
770 
771     while (!g_queue_is_empty(&conn->primary_list)) {
772         pkt = g_queue_pop_head(&conn->primary_list);
773         compare_chr_send(&s->chr_out, pkt->data, pkt->size);
774         packet_destroy(pkt, NULL);
775     }
776     while (!g_queue_is_empty(&conn->secondary_list)) {
777         pkt = g_queue_pop_head(&conn->secondary_list);
778         packet_destroy(pkt, NULL);
779     }
780 }
781 
782 static void colo_compare_class_init(ObjectClass *oc, void *data)
783 {
784     UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
785 
786     ucc->complete = colo_compare_complete;
787 }
788 
789 static void colo_compare_init(Object *obj)
790 {
791     object_property_add_str(obj, "primary_in",
792                             compare_get_pri_indev, compare_set_pri_indev,
793                             NULL);
794     object_property_add_str(obj, "secondary_in",
795                             compare_get_sec_indev, compare_set_sec_indev,
796                             NULL);
797     object_property_add_str(obj, "outdev",
798                             compare_get_outdev, compare_set_outdev,
799                             NULL);
800 }
801 
802 static void colo_compare_finalize(Object *obj)
803 {
804     CompareState *s = COLO_COMPARE(obj);
805 
806     qemu_chr_fe_deinit(&s->chr_pri_in, false);
807     qemu_chr_fe_deinit(&s->chr_sec_in, false);
808     qemu_chr_fe_deinit(&s->chr_out, false);
809 
810     g_main_loop_quit(s->compare_loop);
811     qemu_thread_join(&s->thread);
812 
813     /* Release all unhandled packets after compare thead exited */
814     g_queue_foreach(&s->conn_list, colo_flush_packets, s);
815 
816     g_queue_clear(&s->conn_list);
817 
818     g_hash_table_destroy(s->connection_track_table);
819     g_free(s->pri_indev);
820     g_free(s->sec_indev);
821     g_free(s->outdev);
822 }
823 
824 static const TypeInfo colo_compare_info = {
825     .name = TYPE_COLO_COMPARE,
826     .parent = TYPE_OBJECT,
827     .instance_size = sizeof(CompareState),
828     .instance_init = colo_compare_init,
829     .instance_finalize = colo_compare_finalize,
830     .class_size = sizeof(CompareClass),
831     .class_init = colo_compare_class_init,
832     .interfaces = (InterfaceInfo[]) {
833         { TYPE_USER_CREATABLE },
834         { }
835     }
836 };
837 
838 static void register_types(void)
839 {
840     type_register_static(&colo_compare_info);
841 }
842 
843 type_init(register_types);
844