detect: Add utility module for byte var handling

src/Makefile.am

@@ -96,6 +96,7 @@ detect-asn1.c detect-asn1.h \
 detect-base64-data.c detect-base64-data.h \
 detect-base64-decode.c detect-base64-decode.h \
 detect-bsize.c detect-bsize.h \
+detect-byte.c detect-byte.h \
 detect-byte-extract.c detect-byte-extract.h \
 detect-bytejump.c detect-bytejump.h \
 detect-bytetest.c detect-bytetest.h \

src/detect-byte.c

@@ -0,0 +1,47 @@
+/* Copyright (C) 2020 Open Information Security Foundation
+ *
+ * You can copy, redistribute or modify this Program under the terms of
+ * the GNU General Public License version 2 as published by the Free
+ * Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * version 2 along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+/**
+ * \file
+ *
+ * \author Jeff Lucovsky <jeff@lucovsky.org>
+ */
+
+#include "suricata-common.h"
+#include "detect-byte.h"
+#include "detect-byte-extract.h"
+
+/**
+ * \brief Used to retrieve args from BM.
+ *
+ * \param arg The name of the variable being sought
+ * \param s The signature to check for the variable
+ * \param index When found, the value of the slot within the byte vars
+ *
+ * \retval true A match for the variable was found.
+ * \retval false
+ */
+bool DetectByteRetrieveSMVar(const char *arg, const Signature *s, DetectByteIndexType *index)
+{
+    SigMatch *bed_sm = DetectByteExtractRetrieveSMVar(arg, s);
+    if (bed_sm != NULL) {
+        *index = ((DetectByteExtractData *)bed_sm->ctx)->local_id;
+        return true;
+    }
+
+    return false;
+}

src/detect-byte.h

@@ -0,0 +1,30 @@
+/* Copyright (C) 2020 Open Information Security Foundation
+ *
+ * You can copy, redistribute or modify this Program under the terms of
+ * the GNU General Public License version 2 as published by the Free
+ * Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * version 2 along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+/**
+ * \file
+ *
+ * \author Jeff Lucovsky <jeff@lucovsky.org>
+ */
+
+#ifndef __DETECT_BYTE_H__
+#define __DETECT_BYTE_H__
+typedef uint8_t DetectByteIndexType;
+
+bool DetectByteRetrieveSMVar(const char *, const Signature *, DetectByteIndexType *);
+
+#endif /* __DETECT_BYTE_H__ */