Notify dialog windows when OpenVPN state changes

Use a custom message to pass state change notification from OpenVPN
to all top level windows in the thread.  Currently only the pending auth
dialog responds to this message by closing when the state changes.
The state change could be due to timeout, errors or success via
out-of-band authentication which makes the dialog no longer valid.

The case of CR_TEXT messages that do not require a response is handled
in the next commit.

See also issue #440 https://github.com/OpenVPN/openvpn-gui/issues/440

Signed-off-by: Selva Nair <selva.nair@gmail.com>

main.h

@@ -61,6 +61,7 @@
 #define WM_OVPN_IMPORT         (WM_APP + 20)
 #define WM_OVPN_RESCAN         (WM_APP + 21)
 #define WM_OVPN_ECHOMSG        (WM_APP + 22)
+#define WM_OVPN_STATE          (WM_APP + 23)
 
 /* bool definitions */
 #define bool int

openvpn.c

@@ -248,6 +248,20 @@ parse_assigned_ip(connection_t *c, const char *msg)
     }
 }
 
+/*
+ * Send a custom message to Window hwnd when state changes
+ * hwnd : handle of the window to which the message is sent
+ * lParam : pointer to the state string (char *) received from
+ *          OpenVPN daemon (e., "CONNECTED")
+ * The function signature matches callback for EnumThreadWindows.
+ */
+BOOL
+NotifyStateChange(HWND hwnd, LPARAM lParam)
+{
+    SendMessage(hwnd, WM_OVPN_STATE, 0, lParam);
+    return TRUE;
+}
+
 /*
  * Handle a state change notification from the OpenVPN management interface
  * Format <TIMESTAMP>,<STATE>,[<MESSAGE>],[<LOCAL_IP>][,<REMOTE_IP>]
@@ -274,6 +288,9 @@ OnStateChange(connection_t *c, char *data)
         return;
     *pos = '\0';
 
+    /* notify the all windows in the thread of state change */
+    EnumThreadWindows(GetCurrentThreadId(), NotifyStateChange, (LPARAM) state);
+
     if (strcmp(state, "CONNECTED") == 0)
     {
         parse_assigned_ip(c, pos + 1);
@@ -764,6 +781,20 @@ GenericPassDialogFunc(HWND hwndDlg, UINT msg, WPARAM wParam, LPARAM lParam)
         }
         break;
 
+    case WM_OVPN_STATE: /* state change message is received from OpenVPN daemon */
+        /*
+         * AUTH_PENDING immediately transitions to GET_CONFIG until
+         * auth succeeds or connection restarts/aborts.
+         * Close the CR_TEXT dialog if state changes to anything
+         * other than GET_CONFIG. The state is in lParam.
+         */
+        param = (auth_param_t *) GetProp(hwndDlg, cfgProp);
+        if ((param->flags & FLAG_CR_TYPE_CRTEXT)
+            && strcmp((const char *) lParam, "GET_CONFIG"))
+        {
+            EndDialog(hwndDlg, LOWORD(wParam));
+        }
+        return TRUE;
     case WM_CLOSE:
         EndDialog(hwndDlg, LOWORD(wParam));
         return TRUE;