From 4000c9199b7f91907519a46d692d660012ade090 Mon Sep 17 00:00:00 2001
From: amcewen <amcewen@bcs.org.uk>
Date: Fri, 4 Feb 2011 21:15:42 +0000
Subject: [PATCH] Added new method to UDP to take a hostname rather than an IP
 address.  Part of issue 243

---
 libraries/Ethernet/Udp.cpp | 17 +++++++++++++++++
 libraries/Ethernet/Udp.h   |  3 +++
 2 files changed, 20 insertions(+)

diff --git a/libraries/Ethernet/Udp.cpp b/libraries/Ethernet/Udp.cpp
index a8c98c3f4..2c8b10332 100644
--- a/libraries/Ethernet/Udp.cpp
+++ b/libraries/Ethernet/Udp.cpp
@@ -30,6 +30,7 @@
 #include "socket.h"
 #include "Ethernet.h"
 #include "Udp.h"
+#include "Dns.h"
 
 /* Constructor */
 UDP::UDP() : _sock(MAX_SOCK_NUM) {}
@@ -74,6 +75,22 @@ void UDP::stop()
   _sock = MAX_SOCK_NUM;
 }
 
+int UDP::beginPacket(const char *host, uint16_t port)
+{
+  // Look up the host first
+  int ret = 0;
+  DNSClient dns;
+  IPAddress remote_addr;
+
+  dns.begin(Ethernet.dnsServerIP());
+  ret = dns.getHostByName(host, remote_addr);
+  if (ret == 1) {
+    return beginPacket(remote_addr, port);
+  } else {
+    return ret;
+  }
+}
+
 int UDP::beginPacket(IPAddress ip, uint16_t port)
 {
   _offset = 0;
diff --git a/libraries/Ethernet/Udp.h b/libraries/Ethernet/Udp.h
index 8cd3b065a..99df53f15 100644
--- a/libraries/Ethernet/Udp.h
+++ b/libraries/Ethernet/Udp.h
@@ -60,6 +60,9 @@ public:
   // Start building up a packet to send to the remote host specific in ip and port
   // Returns 1 if successful, 0 if there was a problem with the supplied IP address or port
   int beginPacket(IPAddress ip, uint16_t port);
+  // Start building up a packet to send to the remote host specific in host and port
+  // Returns 1 if successful, 0 if there was a problem resolving the hostname or port
+  int beginPacket(const char *host, uint16_t port);
   // Finish off this packet and send it
   // Returns 1 if the packet was sent successfully, 0 if there was an error
   int endPacket();