Add 'stream-event' keyword.

This patch adds an alias to the 'engine-event' keyword. It is now
possible to access to the stream events via the 'stream-event'
keyword. A simple transformation is done:
    stream-event:reassembly_segment_before_base_seq
is a shortcut for:
    engine-event:stream.reassembly_segment_before_base_seq

src/detect-engine-event.c

@@ -47,6 +47,7 @@ static pcre_extra *parse_regex_study;
 
 int DetectEngineEventMatch (ThreadVars *, DetectEngineThreadCtx *, Packet *, Signature *, SigMatch *);
 static int DetectEngineEventSetup (DetectEngineCtx *, Signature *, char *);
+static int DetectStreamEventSetup (DetectEngineCtx *, Signature *, char *);
 void EngineEventRegisterTests(void);
 
 
@@ -67,6 +68,13 @@ void DetectEngineEventRegister (void) {
     sigmatch_table[DETECT_DECODE_EVENT].Free  = NULL;
     sigmatch_table[DETECT_DECODE_EVENT].flags |= SIGMATCH_DEONLY_COMPAT;
 
+    sigmatch_table[DETECT_STREAM_EVENT].name = "stream-event";
+    sigmatch_table[DETECT_STREAM_EVENT].Match = DetectEngineEventMatch;
+    sigmatch_table[DETECT_STREAM_EVENT].Setup = DetectStreamEventSetup;
+    sigmatch_table[DETECT_STREAM_EVENT].Free  = NULL;
+    sigmatch_table[DETECT_STREAM_EVENT].flags |= SIGMATCH_DEONLY_COMPAT;
+
+
     const char *eb;
     int eo;
     int opts = 0;
@@ -207,6 +215,7 @@ error:
     return -1;
 }
 
+
 /**
  * \brief this function will free memory associated with DetectEngineEventData
  *
@@ -216,6 +225,19 @@ void DetectEngineEventFree(DetectEngineEventData *de) {
     if(de) SCFree(de);
 }
 
+/**
+ * \brief this function Setup the 'stream-event' keyword by resolving the alias
+*/
+static int DetectStreamEventSetup (DetectEngineCtx *de_ctx, Signature *s, char *rawstr)
+{
+    char srawstr[MAX_SUBSTRINGS * 2] = "stream.";
+
+    /* stream:$EVENT alias command develop as decode-event:stream.$EVENT */
+    strncat(srawstr, rawstr, 2 * MAX_SUBSTRINGS - strlen("stream.") - 1);
+
+    return DetectEngineEventSetup (de_ctx, s, srawstr);
+}
+
 /*
  * ONLY TESTS BELOW THIS COMMENT
  */

src/detect.h

@@ -1013,6 +1013,7 @@ enum {
     DETECT_ASN1,
 
     DETECT_ENGINE_EVENT,
+    DETECT_STREAM_EVENT,
 
     /* make sure this stays last */
     DETECT_TBLSIZE,