diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 31a38bde69ef..fbf11562b54c 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -1229,7 +1229,7 @@ int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to,
 		unsigned int maxnonfragsize, headersize;
 
 		headersize = sizeof(struct ipv6hdr) +
-			     (opt ? opt->tot_len : 0) +
+			     (opt ? opt->opt_flen + opt->opt_nflen : 0) +
 			     (dst_allfrag(&rt->dst) ?
 			      sizeof(struct frag_hdr) : 0) +
 			     rt->rt6i_nfheader_len;