DongEun Koak
DnsQuery for NetworkSocketAPI
Fork of
DnsQuery
by 
NetworkSocketAPI
Diff: DnsQuery.cpp
- Revision:
- 18:2cb1fffed50c
- Parent:
- 17:18a6b52be896
- Child:
- 19:4c6f4b6036e6
--- a/DnsQuery.cpp Tue Apr 05 23:39:38 2016 +0000
+++ b/DnsQuery.cpp Tue Apr 19 18:29:55 2016 -0500
@@ -1,216 +1,216 @@
-/* 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.
- */
-#include "DnsQuery.h"
-#include <stdio.h>
-#include <string.h>
-
-
-#define DNS_COUNT (sizeof DNS_IPS / sizeof DNS_IPS[0])
-const char *DNS_IPS[] = {
- "8.8.8.8",
- "209.244.0.3",
- "84.200.69.80",
- "8.26.56.26",
- "208.67.222.222"
-};
-
-static bool isIP(const char *host)
-{
- int i;
-
- for (i = 0; host[i]; i++) {
- if (!(host[i] >= '0' && host[i] <= '9') && host[i] != '.') {
- return false;
- }
- }
-
- // Ending with '.' garuntees host
- if (i > 0 && host[i-1] == '.') {
- return false;
- }
-
- return true;
-}
-
-
-static bool parseRR(uint8_t *resp, int &c, char *adr)
-{
- int n = 0;
- while((n=resp[c++]) != 0) {
- if ((n & 0xc0) != 0) {
- // This is a link
- c++;
- break;
- } else {
- // skip this segment, not interested in string domain names
- c+= n;
- }
- }
-
- int TYPE = (((int)resp[c])<<8) + resp[c+1];
- int CLASS = (((int)resp[c+2])<<8) + resp[c+3];
- int RDLENGTH = (((int)resp[c+8])<<8) + resp[c+9];
-
- c+= 10;
- if ((CLASS == 1) && (TYPE == 1)) {
- sprintf(adr,"%d.%d.%d.%d", resp[c], resp[c+1], resp[c+2], resp[c+3]);
- c+= RDLENGTH;
- return true;
- }
- c+= RDLENGTH;
-
- return false;
-}
-
-
-static bool resolve(unsigned char *resp, char *ipaddress)
-{
-
- int ID = (((int)resp[0]) <<8) + resp[1];
- int QR = resp[2] >>7;
- int Opcode = (resp[2]>>3) & 0x0F;
- int RCODE = (resp[3] & 0x0F);
- int ANCOUNT = (((int)resp[6])<<8)+ resp[7];
-
- if ((ID != 1) || (QR != 1) || (Opcode != 0) || (RCODE != 0)) {
- return false;
- }
-
- int c = 12;
- int d;
- // Skip domain question
- while( (d=resp[c++]) != 0) {
- c+=d;
- }
- c+= 4; // skip QTYPE and QCLASS
-
- // Here comes the resource record
- for (int ans = 0 ; ans < ANCOUNT; ans++) {
- if (parseRR(resp, c, ipaddress)) {
- return true;
- }
- }
-
- return false;
-}
-
-static int32_t query(UDPSocket *socket, const SocketAddress &addr, const char *hostname, char *ipaddress)
-{
- int len = 0;
- if (hostname == NULL) {
- return false;
- }
- len = strlen(hostname);
- if ((len > 128) || (len == 0)) {
- return false;
- }
-
- int packetlen = /* size of HEADER structure */ 12 + /* size of QUESTION Structure */5 + len + 1;
- uint8_t *packet = new uint8_t[packetlen]; /* this is the UDP packet to send to the DNS */
- if (packet == NULL) {
- return false;
- }
-
- // Fill the header
- memset(packet, 0, packetlen);
- packet[1] = 1; // ID = 1
- packet[5] = 1; // QDCOUNT = 1 (contains one question)
- packet[2] = 1; // recursion requested
-
- int c = 13; // point to NAME element in question section or request
- int cnt = 12; // points to the counter of
- packet[cnt] = 0;
- for (int i = 0 ; i < len ; i++) {
- if (hostname[i] != '.') {
- // Copy the character and increment the character counter
- packet[cnt]++;
- packet[c++] = hostname[i];
- } else {
- // Finished with this part, so go to the next
- cnt = c++;
- packet[cnt] = 0;
- }
- }
-
- // Terminate this domain name with a zero entry
- packet[c++] = 0;
-
- // Set QTYPE
- packet[c++] = 0;
- packet[c++] = 1;
- // Set QCLASS
- packet[c++] = 0;
- packet[c++] = 1;
-
-
- if (socket->sendto(addr, packet, packetlen) < 0) {
- delete packet;
- return false;
- }
- delete packet;
-
- packet = new uint8_t [1024];
-
- // Receive the answer from DNS
- int response_length = 0;
- response_length = socket->recvfrom(NULL, packet, 1024);
-
- if (response_length > 0 ) {
- if (!resolve(packet, ipaddress)) {
- delete packet;
- return NSAPI_ERROR_DNS_FAILURE;
- }
-
- // cleanup and return
- delete packet;
- return 0;
- }
-
- delete packet;
- return NSAPI_ERROR_DNS_FAILURE;
-}
-
-int32_t dnsQuery(NetworkInterface *iface, const char *host, char *ip)
-{
- if (isIP(host)) {
- strcpy(ip, host);
- return 0;
- }
-
- UDPSocket sock(iface);
-
- for (unsigned i = 0; i < DNS_COUNT; i++) {
- return query(&sock, SocketAddress(DNS_IPS[0], 53), host, ip);
- }
-
- return NSAPI_ERROR_DNS_FAILURE;
-}
-
-int32_t dnsQuery(UDPSocket *socket, const char *host, char *ip)
-{
- if (isIP(host)) {
- strcpy(ip, host);
- return 0;
- }
-
- for (unsigned i = 0; i < DNS_COUNT; i++) {
- return query(socket, SocketAddress(DNS_IPS[0], 53), host, ip);
- }
-
- return NSAPI_ERROR_DNS_FAILURE;
-}
+/* 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.
+ */
+#include "DnsQuery.h"
+#include <stdio.h>
+#include <string.h>
+
+
+#define DNS_COUNT (sizeof DNS_IPS / sizeof DNS_IPS[0])
+const char *DNS_IPS[] = {
+ "8.8.8.8",
+ "209.244.0.3",
+ "84.200.69.80",
+ "8.26.56.26",
+ "208.67.222.222"
+};
+
+static bool isIP(const char *host)
+{
+ int i;
+
+ for (i = 0; host[i]; i++) {
+ if (!(host[i] >= '0' && host[i] <= '9') && host[i] != '.') {
+ return false;
+ }
+ }
+
+ // Ending with '.' garuntees host
+ if (i > 0 && host[i-1] == '.') {
+ return false;
+ }
+
+ return true;
+}
+
+
+static bool parseRR(uint8_t *resp, int &c, char *adr)
+{
+ int n = 0;
+ while((n=resp[c++]) != 0) {
+ if ((n & 0xc0) != 0) {
+ // This is a link
+ c++;
+ break;
+ } else {
+ // skip this segment, not interested in string domain names
+ c+= n;
+ }
+ }
+
+ int TYPE = (((int)resp[c])<<8) + resp[c+1];
+ int CLASS = (((int)resp[c+2])<<8) + resp[c+3];
+ int RDLENGTH = (((int)resp[c+8])<<8) + resp[c+9];
+
+ c+= 10;
+ if ((CLASS == 1) && (TYPE == 1)) {
+ sprintf(adr,"%d.%d.%d.%d", resp[c], resp[c+1], resp[c+2], resp[c+3]);
+ c+= RDLENGTH;
+ return true;
+ }
+ c+= RDLENGTH;
+
+ return false;
+}
+
+
+static bool resolve(unsigned char *resp, char *ipaddress)
+{
+
+ int ID = (((int)resp[0]) <<8) + resp[1];
+ int QR = resp[2] >>7;
+ int Opcode = (resp[2]>>3) & 0x0F;
+ int RCODE = (resp[3] & 0x0F);
+ int ANCOUNT = (((int)resp[6])<<8)+ resp[7];
+
+ if ((ID != 1) || (QR != 1) || (Opcode != 0) || (RCODE != 0)) {
+ return false;
+ }
+
+ int c = 12;
+ int d;
+ // Skip domain question
+ while( (d=resp[c++]) != 0) {
+ c+=d;
+ }
+ c+= 4; // skip QTYPE and QCLASS
+
+ // Here comes the resource record
+ for (int ans = 0 ; ans < ANCOUNT; ans++) {
+ if (parseRR(resp, c, ipaddress)) {
+ return true;
+ }
+ }
+
+ return false;
+}
+
+static int32_t query(UDPSocket *socket, const SocketAddress &addr, const char *hostname, char *ipaddress)
+{
+ int len = 0;
+ if (hostname == NULL) {
+ return false;
+ }
+ len = strlen(hostname);
+ if ((len > 128) || (len == 0)) {
+ return false;
+ }
+
+ int packetlen = /* size of HEADER structure */ 12 + /* size of QUESTION Structure */5 + len + 1;
+ uint8_t *packet = new uint8_t[packetlen]; /* this is the UDP packet to send to the DNS */
+ if (packet == NULL) {
+ return false;
+ }
+
+ // Fill the header
+ memset(packet, 0, packetlen);
+ packet[1] = 1; // ID = 1
+ packet[5] = 1; // QDCOUNT = 1 (contains one question)
+ packet[2] = 1; // recursion requested
+
+ int c = 13; // point to NAME element in question section or request
+ int cnt = 12; // points to the counter of
+ packet[cnt] = 0;
+ for (int i = 0 ; i < len ; i++) {
+ if (hostname[i] != '.') {
+ // Copy the character and increment the character counter
+ packet[cnt]++;
+ packet[c++] = hostname[i];
+ } else {
+ // Finished with this part, so go to the next
+ cnt = c++;
+ packet[cnt] = 0;
+ }
+ }
+
+ // Terminate this domain name with a zero entry
+ packet[c++] = 0;
+
+ // Set QTYPE
+ packet[c++] = 0;
+ packet[c++] = 1;
+ // Set QCLASS
+ packet[c++] = 0;
+ packet[c++] = 1;
+
+
+ if (socket->sendto(addr, packet, packetlen) < 0) {
+ delete packet;
+ return false;
+ }
+ delete packet;
+
+ packet = new uint8_t [1024];
+
+ // Receive the answer from DNS
+ int response_length = 0;
+ response_length = socket->recvfrom(NULL, packet, 1024);
+
+ if (response_length > 0 ) {
+ if (!resolve(packet, ipaddress)) {
+ delete packet;
+ return NSAPI_ERROR_DNS_FAILURE;
+ }
+
+ // cleanup and return
+ delete packet;
+ return 0;
+ }
+
+ delete packet;
+ return NSAPI_ERROR_DNS_FAILURE;
+}
+
+int32_t dnsQuery(NetworkStack *iface, const char *host, char *ip)
+{
+ if (isIP(host)) {
+ strcpy(ip, host);
+ return 0;
+ }
+
+ UDPSocket sock(iface);
+
+ for (unsigned i = 0; i < DNS_COUNT; i++) {
+ return query(&sock, SocketAddress(DNS_IPS[0], 53), host, ip);
+ }
+
+ return NSAPI_ERROR_DNS_FAILURE;
+}
+
+int32_t dnsQuery(UDPSocket *socket, const char *host, char *ip)
+{
+ if (isIP(host)) {
+ strcpy(ip, host);
+ return 0;
+ }
+
+ for (unsigned i = 0; i < DNS_COUNT; i++) {
+ return query(socket, SocketAddress(DNS_IPS[0], 53), host, ip);
+ }
+
+ return NSAPI_ERROR_DNS_FAILURE;
+}