Avoid circular lwip pcb list (#53)

* don't close tcp_pcb in CLOSED state

* null pcbs when closing

Author: scareything

lib/tunnel_tcp.c

@@ -170,6 +170,9 @@ int tunneler_tcp_close(struct tcp_pcb *pcb) {
         return 0;
     }
     ZITI_LOG(INFO, "closing %p, state=%d", pcb, pcb->state);
+    if (pcb->state == CLOSED) {
+        return 0;
+    }
     tcp_arg(pcb, NULL);
     tcp_recv(pcb, NULL);
     err_t err = tcp_close(pcb);

lib/ziti_tunnel.c

@@ -177,9 +177,11 @@ int ziti_tunneler_close(tunneler_io_context *tnlr_io_ctx) {
     switch ((*tnlr_io_ctx)->proto) {
         case tun_tcp:
             tunneler_tcp_close((*tnlr_io_ctx)->tcp);
+            (*tnlr_io_ctx)->tcp = NULL;
             break;
         case tun_udp:
             tunneler_udp_close((*tnlr_io_ctx)->udp.pcb);
+            (*tnlr_io_ctx)->udp.pcb = NULL;
             break;
         default:
             ZITI_LOG(ERROR, "unknown proto %d", (*tnlr_io_ctx)->proto);
@@ -272,7 +274,7 @@ static void run_packet_loop(uv_loop_t *loop, tunneler_context tnlr_ctx) {
     }
 
     uv_timer_init(loop, &tnlr_ctx->lwip_timer_req);
-    uv_timer_start(&tnlr_ctx->lwip_timer_req, check_lwip_timeouts, 0, 100);
+    uv_timer_start(&tnlr_ctx->lwip_timer_req, check_lwip_timeouts, 0, 10);
 }
 
 #define _str(x) #x

programs/ziti-edge-tunnel/dnsmasq_manager.c

@@ -37,6 +37,9 @@ static int apply_address(dns_manager *dns, const char *hostname, const char *ip)
     char entry[512];
     int c = snprintf(entry, sizeof(entry), "%s\t%s", ip, hostname);
     FILE *rec = fopen(fname, "wb");
+    if (rec == NULL) {
+        return 1;
+    }
     fwrite(entry, 1, c, rec);
     fflush(rec);
     fclose(rec);