qemu/net/colo.c
Mao Zhongyi f449c9e549 colo: compare the packet based on the tcp sequence number
Packet size some time different or when network is busy.
Based on same payload size, but TCP protocol can not
guarantee send the same one packet in the same way,

like that:
We send this payload:
------------------------------
| header |1|2|3|4|5|6|7|8|9|0|
------------------------------

primary:
ppkt1:
----------------
| header |1|2|3|
----------------
ppkt2:
------------------------
| header |4|5|6|7|8|9|0|
------------------------

secondary:
spkt1:
------------------------------
| header |1|2|3|4|5|6|7|8|9|0|
------------------------------

In the original method, ppkt1 and ppkt2 are different in size and
spkt1, so they can't compare and trigger the checkpoint.

I have tested FTP get 200M and 1G file many times, I found that
the performance was less than 1% of the native.

Now I reconstructed the comparison of TCP packets based on the
TCP sequence number. first of all, ppkt1 and spkt1 have the same
starting sequence number, so they can compare, even though their
length is different. And then ppkt1 with a smaller payload length
is used as the comparison length, if the payload is same, send
out the ppkt1 and record the offset(the length of ppkt1 payload)
in spkt1. The next comparison, ppkt2 and spkt1 can be compared
from the recorded position of spkt1.

like that:
----------------
| header |1|2|3| ppkt1
---------|-----|
         |     |
---------v-----v--------------
| header |1|2|3|4|5|6|7|8|9|0| spkt1
---------------|\------------|
               | \offset     |
      ---------v-------------v
      | header |4|5|6|7|8|9|0| ppkt2
      ------------------------

In this way, the performance can reach native 20% in my multiple
tests.

Cc: Zhang Chen <zhangckid@gmail.com>
Cc: Li Zhijian <lizhijian@cn.fujitsu.com>
Cc: Jason Wang <jasowang@redhat.com>

Signed-off-by: Mao Zhongyi <maozy.fnst@cn.fujitsu.com>
Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com>
Signed-off-by: Zhang Chen <zhangckid@gmail.com>
Reviewed-by: Zhang Chen <zhangckid@gmail.com>
Tested-by: Zhang Chen <zhangckid@gmail.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
2018-01-29 16:05:37 +08:00

224 lines
5.6 KiB
C

/*
* 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 "trace.h"
#include "net/colo.h"
uint32_t connection_key_hash(const void *opaque)
{
const ConnectionKey *key = opaque;
uint32_t a, b, c;
/* Jenkins hash */
a = b = c = JHASH_INITVAL + sizeof(*key);
a += key->src.s_addr;
b += key->dst.s_addr;
c += (key->src_port | key->dst_port << 16);
__jhash_mix(a, b, c);
a += key->ip_proto;
__jhash_final(a, b, c);
return c;
}
int connection_key_equal(const void *key1, const void *key2)
{
return memcmp(key1, key2, sizeof(ConnectionKey)) == 0;
}
int parse_packet_early(Packet *pkt)
{
int network_length;
static const uint8_t vlan[] = {0x81, 0x00};
uint8_t *data = pkt->data + pkt->vnet_hdr_len;
uint16_t l3_proto;
ssize_t l2hdr_len = eth_get_l2_hdr_length(data);
if (pkt->size < ETH_HLEN + pkt->vnet_hdr_len) {
trace_colo_proxy_main("pkt->size < ETH_HLEN");
return 1;
}
/*
* TODO: support vlan.
*/
if (!memcmp(&data[12], vlan, sizeof(vlan))) {
trace_colo_proxy_main("COLO-proxy don't support vlan");
return 1;
}
pkt->network_header = data + l2hdr_len;
const struct iovec l2vec = {
.iov_base = (void *) data,
.iov_len = l2hdr_len
};
l3_proto = eth_get_l3_proto(&l2vec, 1, l2hdr_len);
if (l3_proto != ETH_P_IP) {
return 1;
}
network_length = pkt->ip->ip_hl * 4;
if (pkt->size < l2hdr_len + network_length + pkt->vnet_hdr_len) {
trace_colo_proxy_main("pkt->size < network_header + network_length");
return 1;
}
pkt->transport_header = pkt->network_header + network_length;
return 0;
}
void extract_ip_and_port(uint32_t tmp_ports, ConnectionKey *key, Packet *pkt)
{
key->src = pkt->ip->ip_src;
key->dst = pkt->ip->ip_dst;
key->src_port = ntohs(tmp_ports >> 16);
key->dst_port = ntohs(tmp_ports & 0xffff);
}
void fill_connection_key(Packet *pkt, ConnectionKey *key)
{
uint32_t tmp_ports;
memset(key, 0, sizeof(*key));
key->ip_proto = pkt->ip->ip_p;
switch (key->ip_proto) {
case IPPROTO_TCP:
case IPPROTO_UDP:
case IPPROTO_DCCP:
case IPPROTO_ESP:
case IPPROTO_SCTP:
case IPPROTO_UDPLITE:
tmp_ports = *(uint32_t *)(pkt->transport_header);
extract_ip_and_port(tmp_ports, key, pkt);
break;
case IPPROTO_AH:
tmp_ports = *(uint32_t *)(pkt->transport_header + 4);
extract_ip_and_port(tmp_ports, key, pkt);
break;
default:
break;
}
}
void reverse_connection_key(ConnectionKey *key)
{
struct in_addr tmp_ip;
uint16_t tmp_port;
tmp_ip = key->src;
key->src = key->dst;
key->dst = tmp_ip;
tmp_port = key->src_port;
key->src_port = key->dst_port;
key->dst_port = tmp_port;
}
Connection *connection_new(ConnectionKey *key)
{
Connection *conn = g_slice_new(Connection);
conn->ip_proto = key->ip_proto;
conn->processing = false;
conn->offset = 0;
conn->syn_flag = 0;
conn->pack = 0;
conn->sack = 0;
g_queue_init(&conn->primary_list);
g_queue_init(&conn->secondary_list);
return conn;
}
void connection_destroy(void *opaque)
{
Connection *conn = opaque;
g_queue_foreach(&conn->primary_list, packet_destroy, NULL);
g_queue_clear(&conn->primary_list);
g_queue_foreach(&conn->secondary_list, packet_destroy, NULL);
g_queue_clear(&conn->secondary_list);
g_slice_free(Connection, conn);
}
Packet *packet_new(const void *data, int size, int vnet_hdr_len)
{
Packet *pkt = g_slice_new(Packet);
pkt->data = g_memdup(data, size);
pkt->size = size;
pkt->creation_ms = qemu_clock_get_ms(QEMU_CLOCK_HOST);
pkt->vnet_hdr_len = vnet_hdr_len;
pkt->tcp_seq = 0;
pkt->tcp_ack = 0;
pkt->seq_end = 0;
pkt->header_size = 0;
pkt->payload_size = 0;
pkt->offset = 0;
pkt->flags = 0;
return pkt;
}
void packet_destroy(void *opaque, void *user_data)
{
Packet *pkt = opaque;
g_free(pkt->data);
g_slice_free(Packet, pkt);
}
/*
* Clear hashtable, stop this hash growing really huge
*/
void connection_hashtable_reset(GHashTable *connection_track_table)
{
g_hash_table_remove_all(connection_track_table);
}
/* if not found, create a new connection and add to hash table */
Connection *connection_get(GHashTable *connection_track_table,
ConnectionKey *key,
GQueue *conn_list)
{
Connection *conn = g_hash_table_lookup(connection_track_table, key);
if (conn == NULL) {
ConnectionKey *new_key = g_memdup(key, sizeof(*key));
conn = connection_new(key);
if (g_hash_table_size(connection_track_table) > HASHTABLE_MAX_SIZE) {
trace_colo_proxy_main("colo proxy connection hashtable full,"
" clear it");
connection_hashtable_reset(connection_track_table);
/*
* clear the conn_list
*/
while (!g_queue_is_empty(conn_list)) {
connection_destroy(g_queue_pop_head(conn_list));
}
}
g_hash_table_insert(connection_track_table, new_key, conn);
}
return conn;
}