-extern int utcp_send(struct utcp_connection *connection, void *data, size_t len);
-extern int utcp_recv(struct utcp *utcp, void *data, size_t len);
-extern void utcp_close(struct utcp_connection *connection);
-extern void utcp_abort(struct utcp_connection *connection);
-extern void utcp_shutdown(struct utcp_connection *connection, int how);
-extern void utcp_timeout(struct utcp *utcp);
+extern ssize_t utcp_send(struct utcp_connection *connection, const void *data, size_t len);
+extern ssize_t utcp_recv(struct utcp *utcp, const void *data, size_t len);
+extern int utcp_close(struct utcp_connection *connection);
+extern int utcp_abort(struct utcp_connection *connection);
+extern int utcp_shutdown(struct utcp_connection *connection, int how);
+extern struct timeval utcp_timeout(struct utcp *utcp);
+extern void utcp_set_recv_cb(struct utcp_connection *connection, utcp_recv_t recv);
+extern void utcp_set_poll_cb(struct utcp_connection *connection, utcp_poll_t poll);
+extern void utcp_set_accept_cb(struct utcp *utcp, utcp_accept_t accept, utcp_pre_accept_t pre_accept);
+extern bool utcp_is_active(struct utcp *utcp);
+extern void utcp_abort_all_connections(struct utcp *utcp);
+
+// Global socket options
+
+extern int utcp_get_user_timeout(struct utcp *utcp);
+extern void utcp_set_user_timeout(struct utcp *utcp, int seconds);
+
+extern uint16_t utcp_get_mtu(struct utcp *utcp);
+extern void utcp_set_mtu(struct utcp *utcp, uint16_t mtu);
+
+extern void utcp_reset_timers(struct utcp *utcp);
+
+extern void utcp_offline(struct utcp *utcp, bool offline);
+
+// Per-socket options
+
+extern size_t utcp_get_sndbuf(struct utcp_connection *connection);
+extern void utcp_set_sndbuf(struct utcp_connection *connection, size_t size);
+extern size_t utcp_get_sndbuf_free(struct utcp_connection *connection);
+
+extern size_t utcp_get_rcvbuf(struct utcp_connection *connection);
+extern void utcp_set_rcvbuf(struct utcp_connection *connection, size_t size);
+extern size_t utcp_get_rcvbuf_free(struct utcp_connection *connection);
+
+extern size_t utcp_get_sendq(struct utcp_connection *connection);
+extern size_t utcp_get_recvq(struct utcp_connection *connection);
+
+extern bool utcp_get_nodelay(struct utcp_connection *connection);
+extern void utcp_set_nodelay(struct utcp_connection *connection, bool nodelay);
+
+extern bool utcp_get_keepalive(struct utcp_connection *connection);
+extern void utcp_set_keepalive(struct utcp_connection *connection, bool keepalive);
+
+extern size_t utcp_get_outq(struct utcp_connection *connection);
+
+extern void utcp_expect_data(struct utcp_connection *connection, bool expect);