diff --git a/lib/ipv4.h b/lib/ipv4.h
index d136536c..a6720361 100644
--- a/lib/ipv4.h
+++ b/lib/ipv4.h
@@ -56,6 +56,7 @@ typedef u32 ip_addr;
 #define ipa_class_mask(x) x = _MI(ipv4_class_mask(_I(x)))
 #define ipa_from_u32(x) _MI(x)
 #define ipa_to_u32(x) _I(x)
+#define ipa_compare(x,y) ipv4_compare(_I(x),_I(y))
 
 int ipv4_classify(u32);
 u32 ipv4_class_mask(u32);
@@ -68,4 +69,9 @@ static inline unsigned ipv4_hash(u32 a)
   return a & 0xffff;
 }
 
+static inline int ipv4_compare(u32 x, u32 y)
+{
+  return (x > y) - (x < y);
+}
+
 #endif