Diff: DnsQuery.h

Revision:

0:fff4b9055396

Child:

1:5d978992a518

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/DnsQuery.h	Tue Jul 14 20:48:12 2015 +0000
@@ -0,0 +1,90 @@
+/* Copyright (c) 2013 Henry Leinen (henry[dot]leinen [at] online [dot] de)
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of this software
+ * and associated documentation files (the "Software"), to deal in the Software without restriction,
+ * including without limitation the rights to use, copy, modify, merge, publish, distribute,
+ * sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all copies or
+ * substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
+ * BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+ * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+#ifndef __DNSQUERY_H__
+#define __DNSQUERY_H__
+
+#include "Endpoint.h"
+#include "UDPSocket.h"
+typedef struct {
+    union {
+        struct {
+            char o1, o2, o3, o4;
+        };
+        char o[4];
+    } sin_addr;
+    operator char* () { return (char*)this; }
+    char* string_format() { 
+        char ip[7];
+        sprintf(ip,"%d.%d.%d.%d", this->sin_addr.o1, this->sin_addr.o2, this->sin_addr.o3, this->sin_addr.o4);
+        return ip;
+    }
+} IPADDRESS_t;
+
+/** Class DnsQuery implements DNS over UDP functionality.
+  * Example as a typical use case :
+  * @code
+  * #include "mbed.h"
+  * #include "DnsQuery.h"
+  *
+  * void main(void)
+  * {
+  *     IPADDRESS_t ipAddress;  // will receive the ip address of the host
+  *     IPADDRESS_t dnsIp = { 192, 168, 178, 1 };      // Ip Address of the DNS server
+  *     
+  *     DnsQuery dns(Wifi::getInstance(), &dnsIp);
+  *     if (dns.gethostbyname("mbed.org", ipAddress)) {
+  *         printf("Ip-Address of mbed.org is %d.%d.%d.%d\n", ipAddress.sin_addr.o1, ipAddress.sin_addr.o2, ipAddress.sin_addr.o3, ipAddress.sin_addr.o4);
+  *     } else {
+  *         printf("Unable to obtain IP-Address\n");
+  *     }
+  * }
+  * @endcode
+  */
+class DnsQuery
+{
+public:
+    /** Constructor to instantiate a DnsQuery object.
+      * @param wifi : A valid pointer to a Wifi Object, which can be used to obtain a UDP socket object.
+      * @param dnsip : A valid pointer which holds the IPAddress of the DNS server to query.
+      */
+    DnsQuery(IPADDRESS_t* dnsip);
+    
+    
+    /** Function gethostbyname implements the functionality to query a domain name server for an IP-Address of a given hostname.
+      * @param hostname : the hostname of interest as a string.
+      * @param ipaddress : a reference to a IPADDRESS_t object which will receive the resolved IP Address of the host in question.
+      * @returns true if successfull, or false otherwise.
+      */
+    static bool gethostbyname(char* hostname, IPADDRESS_t &ipaddress);
+    /** Function gethostbyname implements the functionality to query a domain name server for an IP-Address of a given hostname.
+      * @param hostname : the hostname of interest as a string.
+      * @param ipaddress : a reference to a IPADDRESS_t object which will receive the resolved IP Address of the host in question.
+      * @returns true if successfull, or false otherwise.
+      */
+    bool getIP(char* hostname, IPADDRESS_t &ipaddress);
+protected:
+    bool resolve(char* resp, IPADDRESS_t &ipaddress);
+    bool parseRR(char *resp, int& c, IPADDRESS_t& adr );
+
+protected:
+    Endpoint* _endpoint;
+    IPADDRESS_t _dnsip;
+    char* _string_ip;
+};
+
+#endif // __DNSQUERY_H__
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