fix to use DNS struct

Author: JacobBarthelmeh

examples/mqttnet.c

@@ -419,8 +419,13 @@ static int NetConnect(void *context, const char* host, word16 port,
                         "Use TLS %d", host, port, timeout_ms, mqttCtx->use_tls);
             }
     #ifndef WOLFMQTT_NO_NETX_DNS
+            if (sock->dnsPtr == NULL) {
+                PRINTF("DNS pointer was NULL and needs set, sock->dnsPtr");
+                return MQTT_CODE_ERROR_NETWORK;
+            }
+
             /* Convert hostname to IP address using NETX DUO DNS */
-            status = nxd_dns_host_by_name_get(sock->ipPtr, (UCHAR *)host,
+            status = nxd_dns_host_by_name_get(sock->dnsPtr, (UCHAR *)host,
                 &ipAddress, timeout_ms);
             if (status != NX_SUCCESS) {
                 PRINTF("DNS lookup failed: %d", status);

examples/mqttnet.h

@@ -57,6 +57,9 @@ typedef struct _SocketContext {
     void* websocket_ctx;
 #endif
 #ifdef HAVE_NETX
+#ifndef WOLFMQTT_NO_NETX_DNS
+    NX_IP_DNS_STRUCT *dnsPtr;
+#endif
     NX_IP     *ipPtr;
     NX_PACKET *nxPacket;
     ULONG     nxOffset;