eve/flow: log tcp reuse as 'reason'

Ticket: #7482.

src/flow-hash.c

@@ -768,6 +768,7 @@ static Flow *TcpReuseReplace(ThreadVars *tv, FlowLookupStruct *fls, FlowBucket *
     old_f->timeout_at = 0;
     /* get some settings that we move over to the new flow */
     FlowThreadId thread_id[2] = { old_f->thread_id[0], old_f->thread_id[1] };
+    old_f->flow_end_flags |= FLOW_END_FLAG_TCPREUSE;
 
     /* flow is unlocked by caller */
 

src/flow.h

@@ -244,6 +244,7 @@ typedef struct AppLayerParserState_ AppLayerParserState;
 #define FLOW_END_FLAG_TIMEOUT   0x02
 #define FLOW_END_FLAG_FORCED    0x04
 #define FLOW_END_FLAG_SHUTDOWN  0x08
+#define FLOW_END_FLAG_TCPREUSE  0x10
 
 /** Mutex or RWLocks for the flow. */
 //#define FLOWLOCK_RWLOCK

src/output-json-flow.c

@@ -258,7 +258,9 @@ static void EveFlowLogJSON(OutputJsonThreadCtx *aft, JsonBuilder *jb, Flow *f)
     }
 
     const char *reason = NULL;
-    if (f->flow_end_flags & FLOW_END_FLAG_FORCED)
+    if (f->flow_end_flags & FLOW_END_FLAG_TCPREUSE)
+        reason = "tcp_reuse";
+    else if (f->flow_end_flags & FLOW_END_FLAG_FORCED)
         reason = "forced";
     else if (f->flow_end_flags & FLOW_END_FLAG_SHUTDOWN)
         reason = "shutdown";