diff --git a/include/patty/ax25/sock.h b/include/patty/ax25/sock.h
index da7c9aa..036a406 100644
--- a/include/patty/ax25/sock.h
+++ b/include/patty/ax25/sock.h
@@ -102,6 +102,9 @@ void patty_ax25_sock_timer_ack_restart(patty_ax25_sock *sock);
 
 void patty_ax25_sock_timer_ack_cancel(patty_ax25_sock *sock);
 
+void patty_ax25_sock_timer_ack_set(patty_ax25_sock *sock,
+                                   struct timeval *timer);
+
 void patty_ax25_sock_timer_ack_sub(patty_ax25_sock *sock,
                                    struct timeval *elapsed);
 
diff --git a/src/sock.c b/src/sock.c
index 9f34dd4..60bc34a 100644
--- a/src/sock.c
+++ b/src/sock.c
@@ -192,6 +192,17 @@ void patty_ax25_sock_timer_ack_cancel(patty_ax25_sock *sock) {
     sock->timer_ack.tv_usec = 0;
 }
 
+void patty_ax25_sock_timer_ack_set(patty_ax25_sock *sock,
+                                   struct timeval *timer) {
+    if (timercmp(&sock->timer_ack, timer, >)) {
+        struct timeval res;
+
+        timeradd(timer, &sock->timer_ack, &res);
+
+        memcpy(timer, &res, sizeof(*timer));
+    }
+}
+
 void patty_ax25_sock_timer_ack_sub(patty_ax25_sock *sock,
                                    struct timeval *elapsed) {
     struct timeval res;