decode/tcp: reduce size needed for tracking WSCALE

Part of effort to make Packet more compact.

Ticket: #6938.

src/decode-tcp.c

@@ -89,10 +89,16 @@ static void DecodeTCPOptions(Packet *p, const uint8_t *pkt, uint16_t pktlen)
                     if (olen != TCP_OPT_WS_LEN) {
                         ENGINE_SET_EVENT(p,TCP_OPT_INVALID_LEN);
                     } else {
-                        if (p->tcpvars.ws.type != 0) {
+                        if (p->tcpvars.wscale_set != 0) {
                             ENGINE_SET_EVENT(p,TCP_OPT_DUPLICATE);
                         } else {
-                            SET_OPTS(p->tcpvars.ws, tcp_opts[tcp_opt_cnt]);
+                            p->tcpvars.wscale_set = 1;
+                            const uint8_t wscale = *(tcp_opts[tcp_opt_cnt].data);
+                            if (wscale <= TCP_WSCALE_MAX) {
+                                p->tcpvars.wscale = wscale;
+                            } else {
+                                p->tcpvars.wscale = 0;
+                            }
                         }
                     }
                     break;

src/decode-tcp.h

@@ -90,16 +90,14 @@
 /** macro for getting the second timestamp from the packet in host order. */
 #define TCP_GET_TSECR(p)                    ((p)->tcpvars.ts_ecr)
 
-#define TCP_HAS_WSCALE(p)                   ((p)->tcpvars.ws.type == TCP_OPT_WS)
+#define TCP_HAS_WSCALE(p)                   ((p)->tcpvars.wscale_set)
 #define TCP_HAS_SACK(p)                     ((p)->tcpvars.sack.type == TCP_OPT_SACK)
 #define TCP_HAS_TS(p)                       ((p)->tcpvars.ts_set)
 #define TCP_HAS_MSS(p)                      ((p)->tcpvars.mss_set)
 #define TCP_HAS_TFO(p)                      ((p)->tcpvars.tfo_set)
 
 /** macro for getting the wscale from the packet. */
-#define TCP_GET_WSCALE(p)                    (TCP_HAS_WSCALE((p)) ? \
-                                                (((*(uint8_t *)(p)->tcpvars.ws.data) <= TCP_WSCALE_MAX) ? \
-                                                  (*(uint8_t *)((p)->tcpvars.ws.data)) : 0) : 0)
+#define TCP_GET_WSCALE(p) (p)->tcpvars.wscale
 
 #define TCP_GET_SACKOK(p)                    (p)->tcpvars.sack_ok
 #define TCP_GET_SACK_PTR(p)                  TCP_HAS_SACK((p)) ? (p)->tcpvars.sack.data : NULL
@@ -160,12 +158,13 @@ typedef struct TCPVars_
     bool sack_ok;
     bool mss_set;
     bool tfo_set;
+    uint8_t wscale_set : 1;
+    uint8_t wscale : 4;
     uint16_t mss;       /**< MSS value in host byte order */
     uint32_t ts_val;    /* host-order */
     uint32_t ts_ecr;    /* host-order */
     uint16_t stream_pkt_flags;
     TCPOpt sack;
-    TCPOpt ws;
 } TCPVars;
 
 #define CLEAR_TCP_PACKET(p)                                                                        \