/*
* 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/error-report.h"
#include "trace.h"
#include "qemu-common.h"
#include "qapi/qmp/qerror.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 "qemu/typedefs.h"
#include "net/queue.h"
#include "sysemu/char.h"
#include "qemu/sockets.h"
#include "qapi-visit.h"
#include "net/colo.h"
#define TYPE_COLO_COMPARE "colo-compare"
#define COLO_COMPARE(obj) \
OBJECT_CHECK(CompareState, (obj), TYPE_COLO_COMPARE)
#define COMPARE_READ_LEN_MAX NET_BUFSIZE
#define MAX_QUEUE_SIZE 1024
/* TODO: Should be configurable */
#define REGULAR_PACKET_CHECK_MS 3000
/*
+ 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;
CharBackend chr_pri_in;
CharBackend chr_sec_in;
CharBackend chr_out;
SocketReadState pri_rs;
SocketReadState sec_rs;
/* connection list: the connections belonged to this NIC could be found
* in this list.
* element type: Connection
*/
GQueue conn_list;
/* hashtable to save connection */
GHashTable *connection_track_table;
/* compare thread, a thread for each NIC */
QemuThread thread;
/* Timer used on the primary to find packets that are never matched */
QEMUTimer *timer;
QemuMutex timer_check_lock;
} CompareState;
typedef struct CompareClass {
ObjectClass parent_class;
} CompareClass;
enum {
PRIMARY_IN = 0,
SECONDARY_IN,
};
static int compare_chr_send(CharBackend *out,
const uint8_t *buf,
uint32_t size);
/*
* 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)
{
ConnectionKey key;
Packet *pkt = NULL;
Connection *conn;
if (mode == PRIMARY_IN) {
pkt = packet_new(s->pri_rs.buf, s->pri_rs.packet_len);
} else {
pkt = packet_new(s->sec_rs.buf, s->sec_rs.packet_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 (g_queue_get_length(&conn->primary_list) <=
MAX_QUEUE_SIZE) {
g_queue_push_tail(&conn->primary_list, pkt);
} else {
error_report("colo compare primary queue size too big,"
"drop packet");
}
} else {
if (g_queue_get_length(&conn->secondary_list) <=
MAX_QUEUE_SIZE) {
g_queue_push_tail(&conn->secondary_list, pkt);
} else {
error_report("colo compare secondary queue size too big,"
"drop packet");
}
}
return 0;
}
/*
* 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_packet_compare(Packet *ppkt, Packet *spkt)
{
trace_colo_compare_ip_info(ppkt->size, inet_ntoa(ppkt->ip->ip_src),
inet_ntoa(ppkt->ip->ip_dst), spkt->size,
inet_ntoa(spkt->ip->ip_src),
inet_ntoa(spkt->ip->ip_dst));
if (ppkt->size == spkt->size) {
return memcmp(ppkt->data, spkt->data, spkt->size);
} else {
return -1;
}
}
/*
* Called from the compare thread on the primary
* for compare tcp packet
* compare_tcp copied from Dr. David Alan Gilbert's branch
*/
static int colo_packet_compare_tcp(Packet *spkt, Packet *ppkt)
{
struct tcphdr *ptcp, *stcp;
int res;
trace_colo_compare_main("compare tcp");
if (ppkt->size != spkt->size) {
if (trace_event_get_state(TRACE_COLO_COMPARE_MISCOMPARE)) {
trace_colo_compare_main("pkt size not same");
}
return -1;
}
ptcp = (struct tcphdr *)ppkt->transport_header;
stcp = (struct tcphdr *)spkt->transport_header;
/*
* The 'identification' field in the IP header is *very* random
* it almost never matches. Fudge this by ignoring differences in
* unfragmented packets; they'll normally sort themselves out if different
* anyway, and it should recover at the TCP level.
* An alternative would be to get both the primary and secondary to rewrite
* somehow; but that would need some sync traffic to sync the state
*/
if (ntohs(ppkt->ip->ip_off) & IP_DF) {
spkt->ip->ip_id = ppkt->ip->ip_id;
/* and the sum will be different if the IDs were different */
spkt->ip->ip_sum = ppkt->ip->ip_sum;
}
res = memcmp(ppkt->data + ETH_HLEN, spkt->data + ETH_HLEN,
(spkt->size - ETH_HLEN));
if (res != 0 && trace_event_get_state(TRACE_COLO_COMPARE_MISCOMPARE)) {
trace_colo_compare_pkt_info_src(inet_ntoa(ppkt->ip->ip_src),
ntohl(stcp->th_seq),
ntohl(stcp->th_ack),
res, stcp->th_flags,
spkt->size);
trace_colo_compare_pkt_info_dst(inet_ntoa(ppkt->ip->ip_dst),
ntohl(ptcp->th_seq),
ntohl(ptcp->th_ack),
res, ptcp->th_flags,
ppkt->size);
qemu_hexdump((char *)ppkt->data, stderr,
"colo-compare ppkt", ppkt->size);
qemu_hexdump((char *)spkt->data, stderr,
"colo-compare spkt", spkt->size);
}
return res;
}
/*
* Called from the compare thread on the primary
* for compare udp packet
*/
static int colo_packet_compare_udp(Packet *spkt, Packet *ppkt)
{
int ret;
trace_colo_compare_main("compare udp");
ret = colo_packet_compare(ppkt, spkt);
if (ret) {
trace_colo_compare_udp_miscompare("primary pkt size", ppkt->size);
qemu_hexdump((char *)ppkt->data, stderr, "colo-compare", ppkt->size);
trace_colo_compare_udp_miscompare("Secondary pkt size", spkt->size);
qemu_hexdump((char *)spkt->data, stderr, "colo-compare", spkt->size);
}
return ret;
}
/*
* Called from the compare thread on the primary
* for compare icmp packet
*/
static int colo_packet_compare_icmp(Packet *spkt, Packet *ppkt)
{
int network_length;
trace_colo_compare_main("compare icmp");
network_length = ppkt->ip->ip_hl * 4;
if (ppkt->size != spkt->size ||
ppkt->size < network_length + ETH_HLEN) {
return -1;
}
if (colo_packet_compare(ppkt, spkt)) {
trace_colo_compare_icmp_miscompare("primary pkt size",
ppkt->size);
qemu_hexdump((char *)ppkt->data, stderr, "colo-compare",
ppkt->size);
trace_colo_compare_icmp_miscompare("Secondary pkt size",
spkt->size);
qemu_hexdump((char *)spkt->data, stderr, "colo-compare",
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)
{
trace_colo_compare_main("compare other");
trace_colo_compare_ip_info(ppkt->size, inet_ntoa(ppkt->ip->ip_src),
inet_ntoa(ppkt->ip->ip_dst), spkt->size,
inet_ntoa(spkt->ip->ip_src),
inet_ntoa(spkt->ip->ip_dst));
return colo_packet_compare(ppkt, spkt);
}
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;
}
}
static void colo_old_packet_check_one_conn(void *opaque,
void *user_data)
{
Connection *conn = opaque;
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 */
/* TODO: colo_notify_checkpoint();*/
}
}
/*
* 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;
g_queue_foreach(&s->conn_list, colo_old_packet_check_one_conn, NULL);
}
/*
* Called from the compare thread on the primary
* for compare connection
*/
static void colo_compare_connection(void *opaque, void *user_data)
{
CompareState *s = user_data;
Connection *conn = opaque;
Packet *pkt = NULL;
GList *result = NULL;
int ret;
while (!g_queue_is_empty(&conn->primary_list) &&
!g_queue_is_empty(&conn->secondary_list)) {
qemu_mutex_lock(&s->timer_check_lock);
pkt = g_queue_pop_tail(&conn->primary_list);
qemu_mutex_unlock(&s->timer_check_lock);
switch (conn->ip_proto) {
case IPPROTO_TCP:
result = g_queue_find_custom(&conn->secondary_list,
pkt, (GCompareFunc)colo_packet_compare_tcp);
break;
case IPPROTO_UDP:
result = g_queue_find_custom(&conn->secondary_list,
pkt, (GCompareFunc)colo_packet_compare_udp);
break;
case IPPROTO_ICMP:
result = g_queue_find_custom(&conn->secondary_list,
pkt, (GCompareFunc)colo_packet_compare_icmp);
break;
default:
result = g_queue_find_custom(&conn->secondary_list,
pkt, (GCompareFunc)colo_packet_compare_other);
break;
}
if (result) {
ret = compare_chr_send(&s->chr_out, pkt->data, pkt->size);
if (ret < 0) {
error_report("colo_send_primary_packet failed");
}
trace_colo_compare_main("packet same and release packet");
g_queue_remove(&conn->secondary_list, result->data);
packet_destroy(pkt, NULL);
} else {
/*
* If one packet arrive late, the secondary_list or
* primary_list will be empty, so we can't compare it
* until next comparison.
*/
trace_colo_compare_main("packet different");
qemu_mutex_lock(&s->timer_check_lock);
g_queue_push_tail(&conn->primary_list, pkt);
qemu_mutex_unlock(&s->timer_check_lock);
/* TODO: colo_notify_checkpoint();*/
break;
}
}
}
static int compare_chr_send(CharBackend *out,
const uint8_t *buf,
uint32_t size)
{
int ret = 0;
uint32_t len = htonl(size);
if (!size) {
return 0;
}
ret = qemu_chr_fe_write_all(out, (uint8_t *)&len, sizeof(len));
if (ret != sizeof(len)) {
goto err;
}
ret = qemu_chr_fe_write_all(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, 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, true);
error_report("colo-compare secondary_in error");
}
}
static void *colo_compare_thread(void *opaque)
{
GMainContext *worker_context;
GMainLoop *compare_loop;
CompareState *s = opaque;
worker_context = g_main_context_new();
qemu_chr_fe_set_handlers(&s->chr_pri_in, compare_chr_can_read,
compare_pri_chr_in, NULL, s, worker_context, true);
qemu_chr_fe_set_handlers(&s->chr_sec_in, compare_chr_can_read,
compare_sec_chr_in, NULL, s, worker_context, true);
compare_loop = g_main_loop_new(worker_context, FALSE);
g_main_loop_run(compare_loop);
g_main_loop_unref(compare_loop);
g_main_context_unref(worker_context);
return NULL;
}
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 void compare_pri_rs_finalize(SocketReadState *pri_rs)
{
CompareState *s = container_of(pri_rs, CompareState, pri_rs);
if (packet_enqueue(s, PRIMARY_IN)) {
trace_colo_compare_main("primary: unsupported packet in");
compare_chr_send(&s->chr_out, pri_rs->buf, pri_rs->packet_len);
} else {
/* compare connection */
g_queue_foreach(&s->conn_list, colo_compare_connection, s);
}
}
static void compare_sec_rs_finalize(SocketReadState *sec_rs)
{
CompareState *s = container_of(sec_rs, CompareState, sec_rs);
if (packet_enqueue(s, SECONDARY_IN)) {
trace_colo_compare_main("secondary: unsupported packet in");
} else {
/* compare connection */
g_queue_foreach(&s->conn_list, colo_compare_connection, s);
}
}
/*
* Return 0 is success.
* Return 1 is failed.
*/
static int find_and_check_chardev(CharDriverState **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;
}
return 0;
}
/*
* 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;
timer_mod(s->timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) +
REGULAR_PACKET_CHECK_MS);
/* if have old packet we will notify checkpoint */
/*
* TODO: Make timer handler run in compare thread
* like qemu_chr_add_handlers_full.
*/
qemu_mutex_lock(&s->timer_check_lock);
colo_old_packet_check(s);
qemu_mutex_unlock(&s->timer_check_lock);
}
/*
* 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);
CharDriverState *chr;
char thread_name[64];
static int compare_id;
if (!s->pri_indev || !s->sec_indev || !s->outdev) {
error_setg(errp, "colo compare needs 'primary_in' ,"
"'secondary_in','outdev' 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);
net_socket_rs_init(&s->sec_rs, compare_sec_rs_finalize);
g_queue_init(&s->conn_list);
qemu_mutex_init(&s->timer_check_lock);
s->connection_track_table = g_hash_table_new_full(connection_key_hash,
connection_key_equal,
g_free,
connection_destroy);
sprintf(thread_name, "colo-compare %d", compare_id);
qemu_thread_create(&s->thread, thread_name,
colo_compare_thread, s,
QEMU_THREAD_JOINABLE);
compare_id++;
/* A regular timer to kick any packets that the secondary doesn't match */
s->timer = timer_new_ms(QEMU_CLOCK_VIRTUAL, /* Only when guest runs */
check_old_packet_regular, s);
timer_mod(s->timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) +
REGULAR_PACKET_CHECK_MS);
return;
}
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)
{
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);
}
static void colo_compare_finalize(Object *obj)
{
CompareState *s = COLO_COMPARE(obj);
qemu_chr_fe_deinit(&s->chr_pri_in);
qemu_chr_fe_deinit(&s->chr_sec_in);
qemu_chr_fe_deinit(&s->chr_out);
g_queue_free(&s->conn_list);
if (qemu_thread_is_self(&s->thread)) {
/* compare connection */
g_queue_foreach(&s->conn_list, colo_compare_connection, s);
qemu_thread_join(&s->thread);
}
if (s->timer) {
timer_del(s->timer);
}
qemu_mutex_destroy(&s->timer_check_lock);
g_free(s->pri_indev);
g_free(s->sec_indev);
g_free(s->outdev);
}
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);
