filter-rewriter: Add TCP state machine and fix memory leak in connection_track_table

We add almost full TCP state machine in filter-rewriter, except
TCPS_LISTEN and some simplify in VM active close FIN states.
The reason for this simplify job is because guest kernel will track
the TCP status and wait 2MSL time too, if client resend the FIN packet,
guest will resend the last ACK, so we needn't wait 2MSL time in filter-rewriter.

After a net connection is closed, we didn't clear its related resources
in connection_track_table, which will lead to memory leak.

Let's track the state of net connection, if it is closed, its related
resources will be cleared up.

Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
Signed-off-by: Zhang Chen <zhangckid@gmail.com>
Signed-off-by: Zhang Chen <chen.zhang@intel.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>

1 files changed, 4 insertions, 5 deletions

diff --git a/net/colo.h b/net/colo.h
index da6c36dcf7..0277e0e9ba 100644
--- a/net/colo.h
+++ b/net/colo.h
@@ -18,6 +18,7 @@
 #include "slirp/slirp.h"
 #include "qemu/jhash.h"
 #include "qemu/timer.h"
+#include "slirp/tcp.h"
 
 #define HASHTABLE_MAX_SIZE 16384
 
@@ -81,11 +82,9 @@ typedef struct Connection {
     uint32_t sack;
     /* offset = secondary_seq - primary_seq */
     tcp_seq  offset;
-    /*
-     * we use this flag update offset func
-     * run once in independent tcp connection
-     */
-    int syn_flag;
+
+    int tcp_state; /* TCP FSM state */
+    tcp_seq fin_ack_seq; /* the seq of 'fin=1,ack=1' */
 } Connection;
 
 uint32_t connection_key_hash(const void *opaque);