--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/sip-out/call_clear.c	Tue Oct 11 23:04:01 2022 -0800
@@ -0,0 +1,66 @@
+/*
+ * In this module we implement final clearing of calls, i.e., freeing
+ * of struct call, and all preliminary steps that need to happen
+ * toward this ultimate end state.
+ */
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/time.h>
+#include <netinet/in.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <strings.h>
+#include <syslog.h>
+#include "../include/out_routes.h"
+#include "call.h"
+
+extern struct call *call_list;
+extern struct timeval cur_event_time;
+
+void
+sip_mark_end_time(call, linger)
+	struct call *call;
+	unsigned linger;
+{
+	call->sip_clear_time = cur_event_time.tv_sec + linger;
+}
+
+void
+check_dead_call(call)
+	struct call *call;
+{
+	if (call->overall_state != OVERALL_STATE_TEARDOWN)
+		return;
+	if (call->mncc)
+		return;
+	if (call->mgw_state != MGW_STATE_NO_EXIST)
+		return;
+	if (call->mgw_xact)
+		return;
+	if (call->sip_call_exists)
+		call->overall_state = OVERALL_STATE_SIP_FINISH;
+	else
+		call->overall_state = OVERALL_STATE_GC;
+}
+
+void
+clear_dead_calls()
+{
+	struct call *call, **pp;
+
+	for (pp = &call_list; *pp; ) {
+		call = *pp;
+		if (call->overall_state == OVERALL_STATE_GC ||
+		    call->overall_state == OVERALL_STATE_SIP_FINISH &&
+		    call->sip_state >= SIP_STATE_ACCEPT_100 &&
+		    cur_event_time.tv_sec >= call->sip_clear_time) {
+			*pp = call->next;
+			free(call);
+			continue;
+		}
+		pp = &call->next;
+	}
+}