When adding an IPv4 host, one can not leave the IPv4-address field if

one has entered invalid data (like an incomplete IP).
Their was no feedback about this, though.
Apply a patch from Peter Postma that gives feedback in this case.
Closes problem noted when re-testing PR 16937.

usr.sbin/sushi/C.msg

@@ -56,6 +56,8 @@ $set 3 run.c stuff
 15 with the spacebar.  Press the ENTER key to return from the list popup.
 16 No help is available for this screen.
 17 Are you sure? (Y/n)
+18 The data entered in this field is invalid.
+19 Please enter the correct information before continuing.
 $set 4 menu titles and stuff
 1 Select choice
 2 Generating form data, please wait

usr.sbin/sushi/scanform.c

@@ -1,4 +1,4 @@
-/*      $NetBSD: scanform.c,v 1.38 2004/03/24 22:03:17 garbled Exp $       */
+/*      $NetBSD: scanform.c,v 1.39 2004/04/05 10:25:12 wiz Exp $       */
 
 /*
  * Copyright (c) 2000 The NetBSD Foundation, Inc.
@@ -1623,6 +1623,27 @@ tab_help(FORM *form)
 	curs_set(1);
 }
 
+static void
+invalid_field_help(void)
+{
+	CDKLABEL *label;
+	char *msg[2];
+
+	msg[0] = catgets(catalog, 3, 18, "The data entered in this field is "
+	    "invalid.");
+	msg[1] = catgets(catalog, 3, 19, "Please enter the correct "
+	    "information before continuing.");
+
+	curs_set(0);
+	label = newCDKLabel(cdkscreen, CENTER, CENTER, msg, 2, TRUE, FALSE);
+	activateCDKLabel(label, NULL);
+	waitCDKLabel(label, 0);
+	destroyCDKLabel(label);
+	touchwin(stdscr);
+	wrefresh(stdscr);
+	curs_set(1);
+}
+
 int
 handle_form(char *basedir, char *path, char **args)
 {
@@ -1692,6 +1713,9 @@ handle_form(char *basedir, char *path, char **args)
 		case E_REQUEST_DENIED:
 			tab_help(menuform);
 			break;
+		case E_INVALID_FIELD:
+			invalid_field_help();
+			break;
 		default:
 			break;
 		}
@@ -1796,6 +1820,9 @@ handle_preform(char *basedir, char *path)
 		case E_REQUEST_DENIED:
 			tab_help(menuform);
 			break;
+		case E_INVALID_FIELD:
+			invalid_field_help();
+			break;
 		default:
 			break;
 		}