diff --git a/bpf_progs/clatd.c b/bpf_progs/clatd.c
index fb7acfa..1ef91e8 100644
--- a/bpf_progs/clatd.c
+++ b/bpf_progs/clatd.c
@@ -104,7 +104,7 @@
     };
 
     // Calculate the IPv4 one's complement checksum of the IPv4 header.
-    __u32 sum = 0;
+    __wsum sum = 0;
     for (int i = 0; i < sizeof(ip) / sizeof(__u16); ++i) {
         sum += ((__u16*)&ip)[i];
     }