30656b097e
We will rewrite tcp packet secondary received and sent. When colo guest is a tcp server. Firstly, client start a tcp handshake. the packet's seq=client_seq, ack=0,flag=SYN. COLO primary guest get this pkt and mirror(filter-mirror) to secondary guest, secondary get it use filter-redirector. Then,primary guest response pkt (seq=primary_seq,ack=client_seq+1,flag=ACK|SYN). secondary guest response pkt (seq=secondary_seq,ack=client_seq+1,flag=ACK|SYN). In here,we use filter-rewriter save the secondary_seq to it's tcp connection. Finally handshake,client send pkt (seq=client_seq+1,ack=primary_seq+1,flag=ACK). Here,filter-rewriter can get primary_seq, and rewrite ack from primary_seq+1 to secondary_seq+1, recalculate checksum. So the secondary tcp connection kept good. When we send/recv packet. client send pkt(seq=client_seq+1+data_len,ack=primary_seq+1,flag=ACK|PSH). filter-rewriter rewrite ack and send to secondary guest. primary guest response pkt (seq=primary_seq+1,ack=client_seq+1+data_len,flag=ACK) secondary guest response pkt (seq=secondary_seq+1,ack=client_seq+1+data_len,flag=ACK) we rewrite secondary guest seq from secondary_seq+1 to primary_seq+1. So tcp connection kept good. In code We use offset( = secondary_seq - primary_seq ) to rewrite seq or ack. handle_primary_tcp_pkt: tcp_pkt->th_ack += offset; handle_secondary_tcp_pkt: tcp_pkt->th_seq -= offset; Signed-off-by: Zhang Chen <zhangchen.fnst@cn.fujitsu.com> Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com> Signed-off-by: Wen Congyang <wency@cn.fujitsu.com> Signed-off-by: Jason Wang <jasowang@redhat.com>
89 lines
2.4 KiB
C
89 lines
2.4 KiB
C
/*
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* COarse-grain LOck-stepping Virtual Machines for Non-stop Service (COLO)
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* (a.k.a. Fault Tolerance or Continuous Replication)
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*
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* Copyright (c) 2016 HUAWEI TECHNOLOGIES CO., LTD.
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* Copyright (c) 2016 FUJITSU LIMITED
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* Copyright (c) 2016 Intel Corporation
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*
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* Author: Zhang Chen <zhangchen.fnst@cn.fujitsu.com>
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*
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* This work is licensed under the terms of the GNU GPL, version 2 or
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* later. See the COPYING file in the top-level directory.
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*/
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#ifndef QEMU_COLO_PROXY_H
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#define QEMU_COLO_PROXY_H
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#include "slirp/slirp.h"
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#include "qemu/jhash.h"
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#include "qemu/timer.h"
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#define HASHTABLE_MAX_SIZE 16384
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#ifndef IPPROTO_DCCP
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#define IPPROTO_DCCP 33
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#endif
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#ifndef IPPROTO_SCTP
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#define IPPROTO_SCTP 132
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#endif
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#ifndef IPPROTO_UDPLITE
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#define IPPROTO_UDPLITE 136
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#endif
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typedef struct Packet {
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void *data;
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union {
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uint8_t *network_header;
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struct ip *ip;
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};
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uint8_t *transport_header;
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int size;
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/* Time of packet creation, in wall clock ms */
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int64_t creation_ms;
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} Packet;
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typedef struct ConnectionKey {
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/* (src, dst) must be grouped, in the same way than in IP header */
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struct in_addr src;
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struct in_addr dst;
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uint16_t src_port;
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uint16_t dst_port;
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uint8_t ip_proto;
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} QEMU_PACKED ConnectionKey;
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typedef struct Connection {
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/* connection primary send queue: element type: Packet */
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GQueue primary_list;
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/* connection secondary send queue: element type: Packet */
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GQueue secondary_list;
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/* flag to enqueue unprocessed_connections */
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bool processing;
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uint8_t ip_proto;
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/* offset = secondary_seq - primary_seq */
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tcp_seq offset;
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/*
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* we use this flag update offset func
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* run once in independent tcp connection
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*/
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int syn_flag;
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} Connection;
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uint32_t connection_key_hash(const void *opaque);
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int connection_key_equal(const void *opaque1, const void *opaque2);
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int parse_packet_early(Packet *pkt);
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void fill_connection_key(Packet *pkt, ConnectionKey *key);
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void reverse_connection_key(ConnectionKey *key);
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Connection *connection_new(ConnectionKey *key);
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void connection_destroy(void *opaque);
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Connection *connection_get(GHashTable *connection_track_table,
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ConnectionKey *key,
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GQueue *conn_list);
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void connection_hashtable_reset(GHashTable *connection_track_table);
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Packet *packet_new(const void *data, int size);
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void packet_destroy(void *opaque, void *user_data);
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#endif /* QEMU_COLO_PROXY_H */
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