442 lines
13 KiB
C
442 lines
13 KiB
C
/*
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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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#include "qemu/osdep.h"
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#include "trace.h"
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#include "colo.h"
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#include "net/filter.h"
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#include "net/net.h"
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#include "qemu/error-report.h"
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#include "qom/object.h"
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#include "qemu/main-loop.h"
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#include "qemu/iov.h"
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#include "net/checksum.h"
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#include "net/colo.h"
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#include "migration/colo.h"
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#include "util.h"
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#define TYPE_FILTER_REWRITER "filter-rewriter"
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OBJECT_DECLARE_SIMPLE_TYPE(RewriterState, FILTER_REWRITER)
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#define FAILOVER_MODE_ON true
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#define FAILOVER_MODE_OFF false
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struct RewriterState {
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NetFilterState parent_obj;
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NetQueue *incoming_queue;
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/* hashtable to save connection */
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GHashTable *connection_track_table;
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bool vnet_hdr;
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bool failover_mode;
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};
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static void filter_rewriter_failover_mode(RewriterState *s)
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{
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s->failover_mode = FAILOVER_MODE_ON;
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}
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static void filter_rewriter_flush(NetFilterState *nf)
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{
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RewriterState *s = FILTER_REWRITER(nf);
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if (!qemu_net_queue_flush(s->incoming_queue)) {
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/* Unable to empty the queue, purge remaining packets */
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qemu_net_queue_purge(s->incoming_queue, nf->netdev);
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}
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}
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/*
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* Return 1 on success, if return 0 means the pkt
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* is not TCP packet
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*/
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static int is_tcp_packet(Packet *pkt)
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{
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if (!parse_packet_early(pkt) &&
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pkt->ip->ip_p == IPPROTO_TCP) {
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return 1;
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} else {
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return 0;
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}
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}
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/* handle tcp packet from primary guest */
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static int handle_primary_tcp_pkt(RewriterState *rf,
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Connection *conn,
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Packet *pkt, ConnectionKey *key)
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{
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struct tcp_hdr *tcp_pkt;
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tcp_pkt = (struct tcp_hdr *)pkt->transport_header;
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if (trace_event_get_state_backends(TRACE_COLO_FILTER_REWRITER_PKT_INFO)) {
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trace_colo_filter_rewriter_pkt_info(__func__,
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inet_ntoa(pkt->ip->ip_src), inet_ntoa(pkt->ip->ip_dst),
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ntohl(tcp_pkt->th_seq), ntohl(tcp_pkt->th_ack),
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tcp_pkt->th_flags);
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}
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if (trace_event_get_state_backends(
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TRACE_COLO_FILTER_REWRITER_CONN_OFFSET)) {
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trace_colo_filter_rewriter_conn_offset(conn->offset);
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}
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if (((tcp_pkt->th_flags & (TH_ACK | TH_SYN)) == (TH_ACK | TH_SYN)) &&
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conn->tcp_state == TCPS_SYN_SENT) {
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conn->tcp_state = TCPS_ESTABLISHED;
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}
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if (((tcp_pkt->th_flags & (TH_ACK | TH_SYN)) == TH_SYN)) {
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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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conn->tcp_state = TCPS_SYN_RECEIVED;
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}
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if (((tcp_pkt->th_flags & (TH_ACK | TH_SYN)) == TH_ACK)) {
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if (conn->tcp_state == TCPS_SYN_RECEIVED) {
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/*
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* offset = secondary_seq - primary seq
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* ack packet sent by guest from primary node,
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* so we use th_ack - 1 get primary_seq
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*/
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conn->offset -= (ntohl(tcp_pkt->th_ack) - 1);
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conn->tcp_state = TCPS_ESTABLISHED;
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}
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if (conn->offset) {
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/* handle packets to the secondary from the primary */
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tcp_pkt->th_ack = htonl(ntohl(tcp_pkt->th_ack) + conn->offset);
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net_checksum_calculate((uint8_t *)pkt->data + pkt->vnet_hdr_len,
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pkt->size - pkt->vnet_hdr_len, CSUM_TCP);
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}
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/*
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* Passive close step 3
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*/
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if ((conn->tcp_state == TCPS_LAST_ACK) &&
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(ntohl(tcp_pkt->th_ack) == (conn->fin_ack_seq + 1))) {
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conn->tcp_state = TCPS_CLOSED;
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g_hash_table_remove(rf->connection_track_table, key);
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}
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}
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if ((tcp_pkt->th_flags & TH_FIN) == TH_FIN) {
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/*
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* Passive close.
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* Step 1:
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* The *server* side of this connect is VM, *client* tries to close
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* the connection. We will into CLOSE_WAIT status.
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*
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* Step 2:
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* In this step we will into LAST_ACK status.
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*
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* We got 'fin=1, ack=1' packet from server side, we need to
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* record the seq of 'fin=1, ack=1' packet.
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*
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* Step 3:
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* We got 'ack=1' packets from client side, it acks 'fin=1, ack=1'
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* packet from server side. From this point, we can ensure that there
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* will be no packets in the connection, except that, some errors
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* happen between the path of 'filter object' and vNIC, if this rare
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* case really happen, we can still create a new connection,
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* So it is safe to remove the connection from connection_track_table.
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*
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*/
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if (conn->tcp_state == TCPS_ESTABLISHED) {
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conn->tcp_state = TCPS_CLOSE_WAIT;
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}
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/*
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* Active close step 2.
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*/
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if (conn->tcp_state == TCPS_FIN_WAIT_1) {
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/*
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* For simplify implementation, we needn't wait 2MSL time
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* in filter rewriter. Because guest kernel will track the
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* TCP status and wait 2MSL time, if client resend the FIN
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* packet, guest will apply the last ACK too.
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* So, we skip the TCPS_TIME_WAIT state here and go straight
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* to TCPS_CLOSED state.
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*/
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conn->tcp_state = TCPS_CLOSED;
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g_hash_table_remove(rf->connection_track_table, key);
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}
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}
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return 0;
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}
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/* handle tcp packet from secondary guest */
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static int handle_secondary_tcp_pkt(RewriterState *rf,
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Connection *conn,
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Packet *pkt, ConnectionKey *key)
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{
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struct tcp_hdr *tcp_pkt;
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tcp_pkt = (struct tcp_hdr *)pkt->transport_header;
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if (trace_event_get_state_backends(TRACE_COLO_FILTER_REWRITER_PKT_INFO)) {
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trace_colo_filter_rewriter_pkt_info(__func__,
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inet_ntoa(pkt->ip->ip_src), inet_ntoa(pkt->ip->ip_dst),
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ntohl(tcp_pkt->th_seq), ntohl(tcp_pkt->th_ack),
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tcp_pkt->th_flags);
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}
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if (trace_event_get_state_backends(
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TRACE_COLO_FILTER_REWRITER_CONN_OFFSET)) {
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trace_colo_filter_rewriter_conn_offset(conn->offset);
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}
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if (conn->tcp_state == TCPS_SYN_RECEIVED &&
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((tcp_pkt->th_flags & (TH_ACK | TH_SYN)) == (TH_ACK | TH_SYN))) {
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/*
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* save offset = secondary_seq and then
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* in handle_primary_tcp_pkt make offset
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* = secondary_seq - primary_seq
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*/
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conn->offset = ntohl(tcp_pkt->th_seq);
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}
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/* VM active connect */
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if (conn->tcp_state == TCPS_CLOSED &&
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((tcp_pkt->th_flags & (TH_ACK | TH_SYN)) == TH_SYN)) {
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conn->tcp_state = TCPS_SYN_SENT;
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}
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if ((tcp_pkt->th_flags & (TH_ACK | TH_SYN)) == TH_ACK) {
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/* Only need to adjust seq while offset is Non-zero */
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if (conn->offset) {
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/* handle packets to the primary from the secondary*/
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tcp_pkt->th_seq = htonl(ntohl(tcp_pkt->th_seq) - conn->offset);
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net_checksum_calculate((uint8_t *)pkt->data + pkt->vnet_hdr_len,
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pkt->size - pkt->vnet_hdr_len, CSUM_TCP);
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}
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}
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/*
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* Passive close step 2:
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*/
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if (conn->tcp_state == TCPS_CLOSE_WAIT &&
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(tcp_pkt->th_flags & (TH_ACK | TH_FIN)) == (TH_ACK | TH_FIN)) {
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conn->fin_ack_seq = ntohl(tcp_pkt->th_seq);
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conn->tcp_state = TCPS_LAST_ACK;
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}
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/*
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* Active close
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*
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* Step 1:
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* The *server* side of this connect is VM, *server* tries to close
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* the connection.
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*
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* Step 2:
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* We will into CLOSE_WAIT status.
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* We simplify the TCPS_FIN_WAIT_2, TCPS_TIME_WAIT and
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* CLOSING status.
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*/
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if (conn->tcp_state == TCPS_ESTABLISHED &&
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(tcp_pkt->th_flags & (TH_ACK | TH_FIN)) == TH_FIN) {
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conn->tcp_state = TCPS_FIN_WAIT_1;
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}
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return 0;
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}
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static ssize_t colo_rewriter_receive_iov(NetFilterState *nf,
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NetClientState *sender,
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unsigned flags,
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const struct iovec *iov,
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int iovcnt,
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NetPacketSent *sent_cb)
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{
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RewriterState *s = FILTER_REWRITER(nf);
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Connection *conn;
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ConnectionKey key;
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Packet *pkt;
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ssize_t size = iov_size(iov, iovcnt);
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ssize_t vnet_hdr_len = 0;
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char *buf = g_malloc0(size);
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iov_to_buf(iov, iovcnt, 0, buf, size);
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if (s->vnet_hdr) {
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vnet_hdr_len = nf->netdev->vnet_hdr_len;
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}
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pkt = packet_new_nocopy(buf, size, vnet_hdr_len);
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/*
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* if we get tcp packet
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* we will rewrite it to make secondary guest's
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* connection established successfully
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*/
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if (pkt && is_tcp_packet(pkt)) {
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fill_connection_key(pkt, &key, sender == nf->netdev);
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/* After failover we needn't change new TCP packet */
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if (s->failover_mode &&
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!connection_has_tracked(s->connection_track_table, &key)) {
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goto out;
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}
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conn = connection_get(s->connection_track_table,
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&key,
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NULL);
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if (sender == nf->netdev) {
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/* NET_FILTER_DIRECTION_TX */
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if (!handle_primary_tcp_pkt(s, conn, pkt, &key)) {
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qemu_net_queue_send(s->incoming_queue, sender, 0,
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(const uint8_t *)pkt->data, pkt->size, NULL);
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packet_destroy(pkt, NULL);
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pkt = NULL;
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/*
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* We block the packet here,after rewrite pkt
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* and will send it
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*/
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return 1;
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}
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} else {
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/* NET_FILTER_DIRECTION_RX */
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if (!handle_secondary_tcp_pkt(s, conn, pkt, &key)) {
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qemu_net_queue_send(s->incoming_queue, sender, 0,
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(const uint8_t *)pkt->data, pkt->size, NULL);
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packet_destroy(pkt, NULL);
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pkt = NULL;
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/*
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* We block the packet here,after rewrite pkt
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* and will send it
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*/
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return 1;
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}
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}
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}
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out:
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packet_destroy(pkt, NULL);
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pkt = NULL;
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return 0;
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}
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static void reset_seq_offset(gpointer key, gpointer value, gpointer user_data)
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{
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Connection *conn = (Connection *)value;
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conn->offset = 0;
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}
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static gboolean offset_is_nonzero(gpointer key,
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gpointer value,
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gpointer user_data)
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{
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Connection *conn = (Connection *)value;
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return conn->offset ? true : false;
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}
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static void colo_rewriter_handle_event(NetFilterState *nf, int event,
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Error **errp)
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{
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RewriterState *rs = FILTER_REWRITER(nf);
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switch (event) {
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case COLO_EVENT_CHECKPOINT:
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g_hash_table_foreach(rs->connection_track_table,
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reset_seq_offset, NULL);
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break;
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case COLO_EVENT_FAILOVER:
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if (!g_hash_table_find(rs->connection_track_table,
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offset_is_nonzero, NULL)) {
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filter_rewriter_failover_mode(rs);
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}
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break;
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default:
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break;
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}
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}
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static void colo_rewriter_cleanup(NetFilterState *nf)
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{
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RewriterState *s = FILTER_REWRITER(nf);
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/* flush packets */
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if (s->incoming_queue) {
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filter_rewriter_flush(nf);
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g_free(s->incoming_queue);
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}
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g_hash_table_destroy(s->connection_track_table);
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}
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static void colo_rewriter_setup(NetFilterState *nf, Error **errp)
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{
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RewriterState *s = FILTER_REWRITER(nf);
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s->connection_track_table = g_hash_table_new_full(connection_key_hash,
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connection_key_equal,
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g_free,
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NULL);
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s->incoming_queue = qemu_new_net_queue(qemu_netfilter_pass_to_next, nf);
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}
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static bool filter_rewriter_get_vnet_hdr(Object *obj, Error **errp)
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{
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RewriterState *s = FILTER_REWRITER(obj);
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return s->vnet_hdr;
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}
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static void filter_rewriter_set_vnet_hdr(Object *obj,
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bool value,
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Error **errp)
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{
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RewriterState *s = FILTER_REWRITER(obj);
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s->vnet_hdr = value;
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}
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static void filter_rewriter_init(Object *obj)
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{
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RewriterState *s = FILTER_REWRITER(obj);
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s->vnet_hdr = false;
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s->failover_mode = FAILOVER_MODE_OFF;
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}
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static void colo_rewriter_class_init(ObjectClass *oc, void *data)
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{
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NetFilterClass *nfc = NETFILTER_CLASS(oc);
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object_class_property_add_bool(oc, "vnet_hdr_support",
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filter_rewriter_get_vnet_hdr,
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filter_rewriter_set_vnet_hdr);
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nfc->setup = colo_rewriter_setup;
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nfc->cleanup = colo_rewriter_cleanup;
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nfc->receive_iov = colo_rewriter_receive_iov;
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nfc->handle_event = colo_rewriter_handle_event;
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}
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static const TypeInfo colo_rewriter_info = {
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.name = TYPE_FILTER_REWRITER,
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.parent = TYPE_NETFILTER,
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.class_init = colo_rewriter_class_init,
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.instance_init = filter_rewriter_init,
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.instance_size = sizeof(RewriterState),
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};
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static void register_types(void)
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{
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type_register_static(&colo_rewriter_info);
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}
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type_init(register_types);
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