diff --git a/networking/isrv.h b/networking/isrv.h
new file mode 100644
index 0000000..780636d
--- /dev/null
+++ b/networking/isrv.h
@@ -0,0 +1,23 @@
+/* opaque structure */
+struct isrv_state_t;
+typedef struct isrv_state_t isrv_state_t;
+
+/* callbacks */
+void isrv_want_rd(isrv_state_t *state, int fd);
+void isrv_want_wr(isrv_state_t *state, int fd);
+void isrv_dont_want_rd(isrv_state_t *state, int fd);
+void isrv_dont_want_wr(isrv_state_t *state, int fd);
+int isrv_register_fd(isrv_state_t *state, int peer, int fd);
+void isrv_close_fd(isrv_state_t *state, int fd);
+int isrv_register_peer(isrv_state_t *state, void *param);
+
+/* driver */
+void isrv_run(
+	int listen_fd,
+	int (*new_peer)(isrv_state_t *state, int fd),
+	int (*do_rd)(int fd, void **),
+	int (*do_wr)(int fd, void **),
+	int (*do_timeout)(void **),
+	int timeout,
+	int linger_timeout
+);