diff --git a/include/common/ist.h b/include/common/ist.h
index bd98ab0..7c60c68 100644
--- a/include/common/ist.h
+++ b/include/common/ist.h
@@ -28,6 +28,7 @@
 #ifndef _COMMON_IST_H
 #define _COMMON_IST_H
 
+#include <ctype.h>
 #include <string.h>
 
 #include <common/config.h>
@@ -243,6 +244,24 @@
 	return 1;
 }
 
+/* returns non-zero if <ist1> equals <ist2>, ignoring the case (empty strings are equal) */
+static inline int isteqi(const struct ist ist1, const struct ist ist2)
+{
+	struct ist l = ist1;
+	struct ist r = ist2;
+
+	if (l.len != r.len)
+		return 0;
+
+	while (l.len--) {
+		if (tolower(*l.ptr) != tolower(*r.ptr))
+			return 0;
+		l.ptr++;
+		r.ptr++;
+	}
+	return 1;
+}
+
 /* returns non-zero if <ist1> equals <ist2> on the first <count> characters
  * (empty strings are equal).
  */