Merge pull request #932 from openziti/avoid-lwip-timer-churn

avoid lwip timer churn

lib/ziti-tunnel/lwip/lwipopts.h

@@ -51,10 +51,12 @@
 
 // APIs
 #define LWIP_RAW 1
+#define LWIP_ARP 0
 #define LWIP_NETCONN 0
 #define LWIP_SOCKET 0
 
 // protocols
+#define LWIP_IPV6_MLD 0
 #define LWIP_IPV6 1                       /* enable ipv6 */
 #define IPV6_FRAG_COPYHEADER 1            /* avoid assert in lwip code when ipv6 is enabled */
 

lib/ziti-tunnel/tunnel_tcp.c

@@ -437,6 +437,7 @@ u8_t recv_tcp(void *tnlr_ctx_arg, struct raw_pcb *pcb, struct pbuf *p, const ip_
     /* now we wait for the tunneler app to call ziti_tunneler_dial_complete() */
 
 done:
+    check_tnlr_timer(tnlr_ctx);
     pbuf_free(p);
     return 1;
 }

lib/ziti-tunnel/ziti_tunnel.c

@@ -486,8 +486,30 @@ static void on_tun_data(uv_poll_t * req, int status, int events) {
     }
 }
 
-static void check_lwip_timeouts(uv_timer_t * handle) {
+static void check_lwip_timeouts(uv_timer_t * timer) {
+    // if timer is not active it may have been a while since
+    // we run timers, let LWIP adjust timeouts
+    if (!uv_is_active((const uv_handle_t *) timer)) {
+        sys_restart_timeouts();
+    }
+
+    // run timers before potentially pausing
     sys_check_timeouts();
+
+    if (tcp_active_pcbs == NULL && tcp_tw_pcbs == NULL) {
+        uv_timer_stop(timer);
+        return;
+    }
+
+    u32_t sleep = sys_timeouts_sleeptime();
+    TNL_LOG(TRACE, "next wake in %d millis", sleep);
+    // second sleep arg is only need to make timer `active` next time
+    // we hit this function to avoid calling sys_restart_timeouts()
+    uv_timer_start(timer, check_lwip_timeouts, sleep, sleep);
+}
+
+void check_tnlr_timer(tunneler_context tnlr_ctx) {
+    check_lwip_timeouts(&tnlr_ctx->lwip_timer_req);
 }
 
 /**
@@ -556,9 +578,9 @@ static void run_packet_loop(uv_loop_t *loop, tunneler_context tnlr_ctx) {
         exit(1);
     }
 
+    // don't run LWIP timers until we have active TCP connections
     uv_timer_init(loop, &tnlr_ctx->lwip_timer_req);
     uv_unref((uv_handle_t *) &tnlr_ctx->lwip_timer_req);
-    uv_timer_start(&tnlr_ctx->lwip_timer_req, check_lwip_timeouts, 0, 10);
 }
 
 typedef struct ziti_tunnel_async_call_s {

lib/ziti-tunnel/ziti_tunnel_priv.h

@@ -157,6 +157,7 @@ struct tunneler_io_ctx_s {
     uint32_t idle_timeout;
 };
 
+extern void check_tnlr_timer(tunneler_context tnlr_ctx);
 extern void free_tunneler_io_context(tunneler_io_context *tnlr_io_ctx_p);
 
 extern void free_intercept(intercept_ctx_t *intercept);