diff --git a/tcp.c b/tcp.c
index 8e3a4c5..9515649 100644
--- a/tcp.c
+++ b/tcp.c
@@ -920,7 +920,7 @@ static void tcp_get_sndbuf(struct tcp_tap_conn *conn)
  * tcp_sock_set_bufsize() - Set SO_RCVBUF and SO_SNDBUF to maximum values
  * @s:		Socket, can be -1 to avoid check in the caller
  */
-void tcp_sock_set_bufsize(const struct ctx *c, int s)
+static void tcp_sock_set_bufsize(const struct ctx *c, int s)
 {
 	int v = INT_MAX / 2; /* Kernel clamps and rounds, no need to check */
 
diff --git a/tcp.h b/tcp.h
index 27b1166..87a6bf9 100644
--- a/tcp.h
+++ b/tcp.h
@@ -23,7 +23,6 @@ int tcp_init(struct ctx *c);
 void tcp_timer(struct ctx *c, const struct timespec *ts);
 void tcp_defer_handler(struct ctx *c);
 
-void tcp_sock_set_bufsize(const struct ctx *c, int s);
 void tcp_update_l2_buf(const unsigned char *eth_d, const unsigned char *eth_s);
 
 /**