diff --git a/ipv4.c b/ipv4.c
index 1d34e1e..89e47e4 100644
--- a/ipv4.c
+++ b/ipv4.c
@@ -139,6 +139,6 @@
   }
 
   // Set the length.
-  ip6_targ->ip6_plen = htons(payload_length(out, pos));
+  ip6_targ->ip6_plen = htons(packet_length(out, pos));
   return iov_len;
 }