Added support for (virtual) W5100 DNS Offloading.

See https://github.com/a2retrosystems/uthernet2/wiki/Virtual-W5100-with-DNS for details.

apps/w5100.c

@@ -108,13 +108,23 @@ static void set_quad(uint16_t addr, uint32_t data)
   *w5100_data = data >> 24;
 }
 
-void w5100_config(uint8_t eth_init)
+bool w5100_init(uint8_t eth_init)
 {
   w5100_mode    = (uint8_t*)(eth_init << 4 | 0xC084);
   w5100_addr_hi = w5100_mode + 1;
   w5100_addr_lo = w5100_mode + 2;
   w5100_data    = w5100_mode + 3;
 
+  // PPP Link Control Protocol Request Timer Register defaults to 0x28
+  // on a real W5100. However, AppleWin features a virtual W5100 that
+  // supports DNS offloading. On that virtual W5100, the (otherwise
+  // anyhow unused) register defaults to 0x00 as detection mechanism.
+  // https://github.com/a2retrosystems/uthernet2/wiki/Virtual-W5100-with-DNS
+  return get_byte(0x0028) == 0x00;
+}
+
+void w5100_config(void)
+{
 #ifdef SINGLE_SOCKET
 
   // IP65 is inhibited so disable the W5100 Ping Block Mode.
@@ -169,14 +179,14 @@ void w5100_config(uint8_t eth_init)
   }
 }
 
-bool w5100_connect(uint32_t addr, uint16_t port)
+static bool w5100_connect(uint16_t port)
 {
-  // Socket x Mode Register: TCP
-  set_byte(SOCK_REG(0x00), 0x01);
-
   // Socket x Source Port Register
   set_word(SOCK_REG(0x04), ip65_random_word());
 
+  // Socket x Destination Port Register
+  set_word(SOCK_REG(0x10), port);
+
   // Socket x Command Register: OPEN
   set_byte(SOCK_REG(0x01), 0x01);
 
@@ -189,12 +199,6 @@ bool w5100_connect(uint32_t addr, uint16_t port)
     }
   }
 
-  // Socket x Destination IP Address Register
-  set_quad(SOCK_REG(0x0C), addr);
-
-  // Socket x Destination Port Register
-  set_word(SOCK_REG(0x10), port);
-
   // Socket x Command Register: CONNECT
   set_byte(SOCK_REG(0x01), 0x04);
 
@@ -214,6 +218,34 @@ bool w5100_connect(uint32_t addr, uint16_t port)
   }
 }
 
+bool w5100_connect_addr(uint32_t addr, uint16_t port)
+{
+  // Socket x Mode Register: TCP, Use No Delayed ACK
+  set_byte(SOCK_REG(0x00), 0x21);
+
+  // Socket x Destination IP Address Register
+  set_quad(SOCK_REG(0x0C), addr);
+
+  return w5100_connect(port);
+}
+
+bool w5100_connect_name(const char* name, uint8_t length, uint16_t port)
+{
+  // Socket x Mode Register: TCP, Use No Delayed ACK, Use DNS Offloading
+  set_byte(SOCK_REG(0x00), 0x29);
+
+  // Socket x DNS name length
+  set_byte(SOCK_REG(0x2A), length);
+
+  // Socket x DNS name chars
+  while (length--)
+  {
+    *w5100_data = *name++;
+  }
+
+  return w5100_connect(port);
+}
+
 bool w5100_connected(void)
 {
   // Socket x Status Register: SOCK_ESTABLISHED ?

apps/w5100.h

@@ -46,13 +46,23 @@ void w5100_data_commit(bool do_send, uint16_t size);
 // to be sent to the server.
 extern volatile uint8_t* w5100_data;
 
+// Initialize this module after the IP65 TCP/IP stack has been initialized.
+// Return true if the (virtual) W5100 supports DNS Offloading.
+// https://github.com/a2retrosystems/uthernet2/wiki/Virtual-W5100-with-DNS
+bool w5100_init(uint8_t eth_init);
+
 // Configure W5100 Ethernet controller with additional information from IP65
 // after the IP65 TCP/IP stack has been configured.
-void w5100_config(uint8_t eth_init);
+void w5100_config(void);
+
+// Connect to server with IP address <addr> on TCP port <port>.
+// Return true if the connection is established, return false otherwise.
+bool w5100_connect_addr(uint32_t addr, uint16_t port);
 
-// Connect to server with IP address <server_addr> on TCP port <server_port>.
+// Connect to server with name <name>, <length> on TCP port <port> using
+// DNS Offloading.
 // Return true if the connection is established, return false otherwise.
-bool w5100_connect(uint32_t addr, uint16_t port);
+bool w5100_connect_name(const char* name, uint8_t length, uint16_t port);
 
 // Check if still connected to server.
 // Return true if the connection is established, return false otherwise.

apps/w5100_http.c

@@ -39,19 +39,10 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #pragma optimize      (on)
 #pragma static-locals (on)
 
-bool w5100_http_open(uint32_t addr, uint16_t port, const char* selector,
-                     char* buffer, size_t length)
+static bool w5100_http_open(const char* selector, char* buffer, size_t length)
 {
   register volatile uint8_t *data = w5100_data;
 
-  printf("Connecting to %s:%d ", dotted_quad(addr), port);
-
-  if (!w5100_connect(addr, port))
-  {
-    printf("- Connect failed\n");
-    return false;
-  }
-
   printf("- Ok\n\nSending request ");
   {
     uint16_t snd;
@@ -177,3 +168,31 @@ bool w5100_http_open(uint32_t addr, uint16_t port, const char* selector,
   }
   return true;
 }
+
+bool w5100_http_open_addr(uint32_t addr, uint16_t port, const char* selector,
+                          char* buffer, size_t length)
+{
+  printf("Connecting to %s:%d ", dotted_quad(addr), port);
+
+  if (!w5100_connect_addr(addr, port))
+  {
+    printf("- Connect failed\n");
+    return false;
+  }
+
+  return w5100_http_open(selector, buffer, length);
+}
+
+bool w5100_http_open_name(const char* name, uint8_t name_length, uint16_t port,
+                          const char* selector, char* buffer, size_t buffer_length)
+{
+  printf("Connecting to port %d ", port);
+
+  if (!w5100_connect_name(name, name_length, port))
+  {
+    printf("- Connect failed\n");
+    return false;
+  }
+
+  return w5100_http_open(selector, buffer, buffer_length);
+}

apps/w5100_http.h

@@ -37,12 +37,20 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include <stdint.h>
 #include <stdbool.h>
 
-// Connect to server with IP address <server_addr> on TCP port <server_port>,
-// then HTTP GET <selector> and consume HTTP response header. Provide feedback
-// on progress to the user via STDOUT. After returning from w5100_http_open()
-// the connection is ready to consume the HTTP body.
+// Connect to server with IP address <addr> on TCP port <port>, then HTTP GET
+// <selector> and consume HTTP response header. Provide feedback on progress
+// to the user via STDOUT. After returning from w5100_http_open_addr(), the
+// connection is ready to consume the HTTP body.
 // Return true if the connection is established, return false otherwise.
-bool w5100_http_open(uint32_t addr, uint16_t port, const char* selector,
-                     char* buffer, size_t length);
+bool w5100_http_open_addr(uint32_t addr, uint16_t port, const char* selector,
+                          char* buffer, size_t length);
+
+// Connect to server with name <name>, <name_length> on TCP port <port> using
+// DNS Offloading, then HTTP GET <selector> and consume HTTP response header.
+// Provide feedback on progress to the user via STDOUT. After returning from
+// w5100_http_open_name(), the connection is ready to consume the HTTP body.
+// Return true if the connection is established, return false otherwise.
+bool w5100_http_open_name(const char* name, uint8_t name_length, uint16_t port,
+                          const char* selector, char* buffer, size_t buffer_length);
 
 #endif

apps/wget65.c

@@ -435,6 +435,7 @@ int main(int, char *argv[])
   uint16_t i;
   char *arg;
   char device;
+  bool Offload_DNS;
   uint8_t eth_init = ETH_INIT_DEFAULT;
 
   if (doesclrscrafterexit())
@@ -481,23 +482,28 @@ int main(int, char *argv[])
   // Abort on Ctrl-C to be consistent with Linenoise
   abort_key = 0x83;
 
-  printf("- Ok\n\nObtaining IP address ");
-  if (dhcp_init())
+  Offload_DNS = w5100_init(eth_init);
+
+  if (!Offload_DNS)
   {
-    ip65_error_exit();
+    printf("- Ok\n\nObtaining IP address ");
+    if (dhcp_init())
+    {
+      ip65_error_exit();
+    }
   }
   printf("- Ok\n\n");
 
   // Copy IP config from IP65 to W5100
-  w5100_config(eth_init);
+  w5100_config();
 
   load_argument("wget.urls");
   while (true)
   {
     arg = get_argument(1, "URL", url_completion);
 
     printf("\n\nProcessing URL ");
-    if (!url_parse(arg, true))
+    if (!url_parse(arg, !Offload_DNS))
     {
       break;
     }
@@ -650,9 +656,21 @@ int main(int, char *argv[])
   save_argument("wget.files");
 
   printf("\n\n");
-  if (!w5100_http_open(url_ip, url_port, url_selector, buffer, sizeof(buffer)))
+  if (Offload_DNS)
   {
-    return EXIT_FAILURE;
+    if (!w5100_http_open_name(url_host, strlen(url_host) - 4, url_port,
+                              url_selector, buffer, sizeof(buffer)))
+    {
+      return EXIT_FAILURE;
+    }
+  }
+  else
+  {
+    if (!w5100_http_open_addr(url_ip, url_port,
+                              url_selector, buffer, sizeof(buffer)))
+    {
+      return EXIT_FAILURE;
+    }
   }
 
   if (device)