VNC: First few lines of initialization code

graphics/vnc/server/Kconfig

@@ -49,4 +49,8 @@ config VNCSERVER_KBDENCODE
 		Use a special encoding of keyboard characters as defined in
 		include/nuttx/input/kbd_coded.h.
 
+config VNCSERVER_IOBUFFER_SIZE
+	int "I/O buffer size
+	default 80
+
 endif # VNCSERVER

graphics/vnc/server/vnc_negotiate.c

@@ -47,6 +47,16 @@
 
 #include "vnc_server.h"
 
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+#if defined(CONFIG_VNCSERVER_PROTO3p3)
+static const char g_vncproto[] = RFB_PROTOCOL_VERSION_3p3;
+#elif defined(CONFIG_VNCSERVER_PROTO3p8)
+static const char g_vncproto[] = RFB_PROTOCOL_VERSION_3p8;
+#endif
+
 /****************************************************************************
  * Private Functions
  ****************************************************************************/
@@ -93,13 +103,60 @@ static void nvc_xyz(FAR struct vnc_session_s *session)
 #ifdef CONFIG_VNCSERVER_PROTO3p3
 int vnc_negotiate(FAR struct vnc_session_s *session)
 {
+  ssize_t nrecvd;
+  size_t len;
+  int errcode;
+
+  /* Inform the client of the VNC protocol */
+
+  len = strlen(g_vncproto);
+  nrecvd = psock_send(&session->connect, g_vncproto, len, 0);
+  if (nrecvd < 0)
+    {
+      goto errout_with_errno;
+    }
+
+  nrecvd = psock_recv(&session->connect, session->iobuf, len, 0);
+  if (nrecvd <= 0)
+    {
+      goto errout_with_errno;
+    }
+
+  /* Tell the client that we won't use any stinkin' security */
+
   return OK;
+
+errout_with_errno:
+  errcode = get_errno();
+
+errout_with_errcode:
+  DEBUGASSERT(errcode > 0);
+  return -errcode;
 }
 #endif
 
 #ifdef CONFIG_VNCSERVER_PROTO3p8
 int vnc_negotiate(FAR struct vnc_session_s *session)
 {
+  ssize_t nbytes;
+
+  /* Inform the client of the VNC protocol */
+
+  len = strlen(g_vncproto);
+  nrecvd = psock_send(&session->connect, g_vncproto, len, 0);
+  if (nrecvd < 0)
+    {
+      goto errout_with_errno;
+    }
+
+  nrecvd = psock_recv(&session->connect, session->iobuf, len, 0);
+  if (nrecvd <= 0)
+    {
+      goto errout_with_errno;
+    }
+
+  /* Offer the client a choice of security -- where None is the only option. */
+
   return OK;
 }
 #endif

graphics/vnc/server/vnc_server.h

@@ -75,12 +75,26 @@
 #  define CONFIG_VNCSERVER_STACKSIZE 2048
 #endif
 
+#ifndef CONFIG_VNCSERVER_IOBUFFER_SIZE
+#  define CONFIG_VNCSERVER_IOBUFFER_SIZE 80
+#endif
+
 /* RFB Port Number */
 
 #define RFB_PORT_BASE       5900
 #define RFB_MAX_DISPLAYS    CONFIG_VNCSERVER_NDISPLAYS
 #define RFB_DISPLAY_PORT(d) (RFB_PORT_BASE + (d))
 
+/* Miscellaneous */
+
+#ifndef MIN
+#  define MIN(a,b) (((a) < (b)) ? (a) : (b))
+#endif
+
+#ifndef MAX
+#  define MAX(a,b) (((a) > (b)) ? (a) : (b))
+#endif
+
 /****************************************************************************
  * Public Types
  ****************************************************************************/
@@ -115,6 +129,10 @@ struct vnc_session_s
   uint8_t bpp;                 /* Bits per pixel */
   struct nxgl_size_s screen;   /* Size of the screen in pixels x rows */
   FAR uint8_t *fb;             /* Allocated local frame buffer */
+ 
+  /* I/O buffer for misc network send/receive */
+
+  uint8_t iobuf[CONFIG_VNCSERVER_IOBUFFER_SIZE];
 };
 
 /****************************************************************************