--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/sip-manual-out/user_cmd.c	Fri Mar 17 14:31:54 2023 -0800
@@ -0,0 +1,34 @@
+/*
+ * In this module we implement stdin command handling, supporting
+ * user-initiated CANCEL and BYE as well as TFO testing commands.
+ */
+
+#include <ctype.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <strings.h>
+
+void
+select_stdin()
+{
+	char buf[256], *cp;
+
+	fgets(buf, sizeof buf, stdin);
+	cp = index(buf, '\n');
+	if (cp) {
+		while (cp > buf && isspace(cp[-1]))
+			cp--;
+		*cp = '\0';
+	}
+	for (cp = buf; isspace(*cp); cp++)
+		;
+	if (!*cp)
+		return;
+	if (!strcmp(cp, "b") || !strcasecmp(cp, "bye"))
+		send_bye_req();
+	else if (!strcmp(cp, "c") || !strcasecmp(cp, "cancel"))
+		send_cancel_req();
+	else
+		fprintf(stderr, "error: non-understood stdin command\n");
+}