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| author | Zhang Chen <zhangchen.fnst@cn.fujitsu.com> | 2016-09-27 10:22:34 +0800 |
|---|---|---|
| committer | Jason Wang <jasowang@redhat.com> | 2016-09-27 17:54:22 +0800 |
| commit | 30656b097e9dd7978d3fe9416cb9f5a421a9e63e (patch) | |
| tree | c6b5ffa87a684d35686d77f436c5bde8b513dbbd /trace-events | |
| parent | afe461240940077e7ea8313e9c547a4898263cd2 (diff) | |
| download | qemu-30656b097e9dd7978d3fe9416cb9f5a421a9e63e.tar.gz | |
filter-rewriter: rewrite tcp packet to keep secondary connection
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>
Diffstat (limited to 'trace-events')
| -rw-r--r-- | trace-events | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/trace-events b/trace-events index b39536852e..1cb9d37ce4 100644 --- a/trace-events +++ b/trace-events @@ -150,6 +150,11 @@ colo_compare_ip_info(int psize, const char *sta, const char *stb, int ssize, con colo_old_packet_check_found(int64_t old_time) "%" PRId64 colo_compare_miscompare(void) "" +# net/filter-rewriter.c +colo_filter_rewriter_debug(void) "" +colo_filter_rewriter_pkt_info(const char *func, const char *src, const char *dst, uint32_t seq, uint32_t ack, uint32_t flag) "%s: src/dst: %s/%s p: seq/ack=%u/%u flags=%x\n" +colo_filter_rewriter_conn_offset(uint32_t offset) ": offset=%u\n" + ### Guest events, keep at bottom # @vaddr: Access' virtual address. |