diff --git a/opacket.c b/opacket.c
index dd443c331..5eae633b6 100644
--- a/opacket.c
+++ b/opacket.c
@@ -319,3 +319,27 @@ packet_read_expect(int expected_type)
 	if ((r = ssh_packet_read_expect(active_state, expected_type)) != 0)
 		sshpkt_fatal(active_state, __func__, r);
 }
+
+void
+packet_disconnect(const char *fmt, ...)
+{
+	char buf[1024];
+	va_list args;
+
+	va_start(args, fmt);
+	vsnprintf(buf, sizeof(buf), fmt, args);
+	va_end(args);
+	ssh_packet_disconnect(active_state, "%s", buf);
+}
+
+void
+packet_send_debug(const char *fmt, ...)
+{
+	char buf[1024];
+	va_list args;
+
+	va_start(args, fmt);
+	vsnprintf(buf, sizeof(buf), fmt, args);
+	va_end(args);
+	ssh_packet_send_debug(active_state, "%s", buf);
+}
diff --git a/opacket.h b/opacket.h
index 16fcb9e28..a0a60e550 100644
--- a/opacket.h
+++ b/opacket.h
@@ -102,10 +102,11 @@ void	 packet_read_expect(int expected_type);
 	ssh_packet_get_string_ptr(active_state, (length_ptr))
 #define packet_get_cstring(length_ptr) \
 	ssh_packet_get_cstring(active_state, (length_ptr))
-#define packet_send_debug(fmt, args...) \
-	ssh_packet_send_debug(active_state, (fmt), ##args)
-#define packet_disconnect(fmt, args...) \
-	ssh_packet_disconnect(active_state, (fmt), ##args)
+void	packet_send_debug(const char *, ...)
+	    __attribute__((format(printf, 1, 2)));
+void	packet_disconnect(const char *, ...)
+	    __attribute__((format(printf, 1, 2)))
+	    __attribute__((noreturn));
 #define packet_have_data_to_write() \
 	ssh_packet_have_data_to_write(active_state)
 #define packet_not_very_much_data_to_write() \