var: Use 16-bit container for type

Issue: 6855: Match sigmatch type field in var and bit structs

src/detect-engine-register.h

@@ -56,8 +56,7 @@ enum DetectKeywordId {
     DETECT_FLOW,
     /* end prefilter sort */
 
-    /* values used in util-var.c go here, to avoid int overflows
-     * TODO update var logic to use a larger type, see #6855. */
+    /* values used in util-var.c go here, to avoid int overflows */
     DETECT_THRESHOLD,
     DETECT_FLOWBITS,
     DETECT_FLOWVAR,

src/detect-engine-threshold.c

@@ -524,8 +524,8 @@ static void FlowThresholdEntryListFree(FlowThresholdEntryList *list)
 /** struct for storing per flow thresholds. This will be stored in the Flow::flowvar list, so it
  * needs to follow the GenericVar header format. */
 typedef struct FlowVarThreshold_ {
-    uint8_t type;
-    uint8_t pad[7];
+    uint16_t type;
+    uint8_t pad[6];
     struct GenericVar_ *next;
     FlowThresholdEntryList *thresholds;
 } FlowVarThreshold;

src/flow-bit.h

@@ -28,8 +28,8 @@
 #include "util-var.h"
 
 typedef struct FlowBit_ {
-    uint8_t type; /* type, DETECT_FLOWBITS in this case */
-    uint8_t pad[3];
+    uint16_t type; /* type, DETECT_FLOWBITS in this case */
+    uint8_t pad[2];
     uint32_t idx; /* name idx */
     GenericVar *next; /* right now just implement this as a list,
                        * in the long run we have think of something

src/flow-var.h

@@ -46,13 +46,14 @@ typedef struct FlowVarTypeInt_ {
 
 /** Generic Flowvar Structure */
 typedef struct FlowVar_ {
-    uint8_t type;       /* type, DETECT_FLOWVAR in this case */
+    uint16_t type; /* type, DETECT_FLOWVAR in this case */
     uint8_t datatype;
-    uint16_t keylen;
+    uint8_t pad;
     uint32_t idx;       /* name idx */
     GenericVar *next;   /* right now just implement this as a list,
                          * in the long run we have think of something
                          * faster. */
+    uint16_t keylen;
     union {
         FlowVarTypeStr fv_str;
         FlowVarTypeInt fv_int;

src/util-var.h

@@ -46,17 +46,16 @@ enum VarTypes {
     VAR_TYPE_IPPAIR_VAR,
 };
 
-/** \todo see ticket #6855. The type field should be 16 bits. */
 typedef struct GenericVar_ {
-    uint8_t type; /**< variable type, uses detection sm_type */
-    uint8_t pad[3];
+    uint16_t type; /**< variable type, uses detection sm_type */
+    uint8_t pad[2];
     uint32_t idx;
     struct GenericVar_ *next;
 } GenericVar;
 
 typedef struct XBit_ {
-    uint8_t type;       /* type, DETECT_XBITS in this case */
-    uint8_t pad[3];
+    uint16_t type; /* type, DETECT_XBITS in this case */
+    uint8_t pad[2];
     uint32_t idx;       /* name idx */
     GenericVar *next;
     uint32_t expire;