ms: Add timer

Currently the MS object is immediately idle when all TBFs are
detached and if no guard is being used. Since the plan is to use the
MS objects to pass information from one TBF to the next one even
across the gap of some seconds of inactivity, a mechanism is needed
to keep the MS objects around for some time.

This commit extends the GprsMs class by a timer that keeps the MS
objects in non-idle state for some time after all TBFs have been
detached. The set_timeout method must be used with a non-zero value
to activate this feature.

Sponsored-by: On-Waves ehf

src/gprs_ms.cpp

@@ -40,11 +40,9 @@ struct GprsMsDefaultCallback: public GprsMs::Callback {
 
 static GprsMsDefaultCallback gprs_default_cb;
 
-
-GprsMs::Guard::Guard(GprsMs *ms) : m_ms(ms)
+GprsMs::Guard::Guard(GprsMs *ms) :
+	m_ms(ms ? ms->ref() : NULL)
 {
-	if (m_ms)
-		m_ms->ref();
 }
 
 GprsMs::Guard::~Guard()
@@ -53,6 +51,19 @@ GprsMs::Guard::~Guard()
 		m_ms->unref();
 }
 
+void GprsMs::timeout(void *priv_)
+{
+	GprsMs *ms = static_cast<GprsMs *>(priv_);
+
+	LOGP(DRLCMAC, LOGL_INFO, "Timeout for MS object, TLLI = 0x%08x\n",
+		ms->tlli());
+
+	if (ms->m_timer.data) {
+		ms->m_timer.data = NULL;
+		ms->unref();
+	}
+}
+
 GprsMs::GprsMs(uint32_t tlli) :
 	m_cb(&gprs_default_cb),
 	m_ul_tbf(NULL),
@@ -68,12 +79,17 @@ GprsMs::GprsMs(uint32_t tlli) :
 	LOGP(DRLCMAC, LOGL_INFO, "Creating MS object, TLLI = 0x%08x\n", tlli);
 
 	m_imsi[0] = 0;
+	memset(&m_timer, 0, sizeof(m_timer));
+	m_timer.cb = GprsMs::timeout;
 }
 
 GprsMs::~GprsMs()
 {
 	LOGP(DRLCMAC, LOGL_INFO, "Destroying MS object, TLLI = 0x%08x\n", tlli());
 
+	if (osmo_timer_pending(&m_timer))
+		osmo_timer_del(&m_timer);
+
 	if (m_ul_tbf) {
 		m_ul_tbf->set_ms(NULL);
 		m_ul_tbf = NULL;
@@ -99,9 +115,10 @@ void GprsMs::operator delete(void* p)
 	talloc_free(p);
 }
 
-void GprsMs::ref()
+GprsMs *GprsMs::ref()
 {
 	m_ref += 1;
+	return this;
 }
 
 void GprsMs::unref()
@@ -112,6 +129,27 @@ void GprsMs::unref()
 		update_status();
 }
 
+void GprsMs::start_timer()
+{
+	if (m_delay == 0)
+		return;
+
+	if (!m_timer.data)
+		m_timer.data = ref();
+
+	osmo_timer_schedule(&m_timer, m_delay, 0);
+}
+
+void GprsMs::stop_timer()
+{
+	if (!m_timer.data)
+		return;
+
+	osmo_timer_del(&m_timer);
+	m_timer.data = NULL;
+	unref();
+}
+
 void GprsMs::attach_tbf(struct gprs_rlcmac_tbf *tbf)
 {
 	if (tbf->direction == GPRS_RLCMAC_DL_TBF)
@@ -134,6 +172,9 @@ void GprsMs::attach_ul_tbf(struct gprs_rlcmac_ul_tbf *tbf)
 		detach_tbf(m_ul_tbf);
 
 	m_ul_tbf = tbf;
+
+	if (tbf)
+		stop_timer();
 }
 
 void GprsMs::attach_dl_tbf(struct gprs_rlcmac_dl_tbf *tbf)
@@ -150,6 +191,9 @@ void GprsMs::attach_dl_tbf(struct gprs_rlcmac_dl_tbf *tbf)
 		detach_tbf(m_dl_tbf);
 
 	m_dl_tbf = tbf;
+
+	if (tbf)
+		stop_timer();
 }
 
 void GprsMs::detach_tbf(gprs_rlcmac_tbf *tbf)
@@ -167,6 +211,9 @@ void GprsMs::detach_tbf(gprs_rlcmac_tbf *tbf)
 	if (tbf->ms() == this)
 		tbf->set_ms(NULL);
 
+	if (!m_dl_tbf && !m_dl_tbf)
+		start_timer();
+
 	update_status();
 }
 

src/gprs_ms.h

@@ -25,6 +25,11 @@ struct gprs_rlcmac_dl_tbf;
 struct gprs_rlcmac_ul_tbf;
 
 #include "cxx_linuxlist.h"
+
+extern "C" {
+	#include <osmocom/core/timer.h>
+}
+
 #include <stdint.h>
 #include <stddef.h>
 
@@ -62,6 +67,8 @@ public:
 	uint8_t ta() const;
 	void set_ta(uint8_t ta);
 
+	void set_timeout(unsigned secs);
+
 	void attach_tbf(gprs_rlcmac_tbf *tbf);
 	void attach_ul_tbf(gprs_rlcmac_ul_tbf *tbf);
 	void attach_dl_tbf(gprs_rlcmac_dl_tbf *tbf);
@@ -76,10 +83,15 @@ public:
 	LListHead<GprsMs>& list() {return this->m_list;}
 	const LListHead<GprsMs>& list() const {return this->m_list;}
 
+	/* internal use */
+	static void timeout(void *priv_);
+
 protected:
 	void update_status();
-	void ref();
+	GprsMs *ref();
 	void unref();
+	void start_timer();
+	void stop_timer();
 
 private:
 	Callback * m_cb;
@@ -96,6 +108,8 @@ private:
 	bool m_is_idle;
 	int m_ref;
 	LListHead<GprsMs> m_list;
+	struct osmo_timer_list m_timer;
+	unsigned m_delay;
 };
 
 inline uint32_t GprsMs::tlli() const
@@ -120,3 +134,8 @@ inline uint8_t GprsMs::ta() const
 {
 	return m_ta;
 }
+
+inline void GprsMs::set_timeout(unsigned secs)
+{
+	m_delay = secs;
+}

tests/ms/MsTest.cpp

@@ -36,6 +36,7 @@ extern "C" {
 }
 
 #include <errno.h>
+#include <unistd.h>
 
 void *tall_pcu_ctx;
 int16_t spoof_mnc = 0, spoof_mcc = 0;
@@ -399,6 +400,74 @@ static void test_ms_storage()
 	printf("=== end %s ===\n", __func__);
 }
 
+static void test_ms_timeout()
+{
+	uint32_t tlli = 0xffeeddbb;
+	gprs_rlcmac_dl_tbf *dl_tbf;
+	gprs_rlcmac_ul_tbf *ul_tbf;
+	GprsMs *ms;
+	static enum {UNKNOWN, IS_IDLE, IS_ACTIVE} last_cb = UNKNOWN;
+
+	struct MyCallback: public GprsMs::Callback {
+		virtual void ms_idle(class GprsMs *ms) {
+			OSMO_ASSERT(ms->is_idle());
+			printf("  ms_idle() was called\n");
+			last_cb = IS_IDLE;
+		}
+		virtual void ms_active(class GprsMs *ms) {
+			OSMO_ASSERT(!ms->is_idle());
+			printf("  ms_active() was called\n");
+			last_cb = IS_ACTIVE;
+		}
+	} cb;
+
+	printf("=== start %s ===\n", __func__);
+
+	ms = new GprsMs(tlli);
+	ms->set_callback(&cb);
+	ms->set_timeout(1);
+
+	OSMO_ASSERT(ms->is_idle());
+
+	dl_tbf = talloc_zero(tall_pcu_ctx, struct gprs_rlcmac_dl_tbf);
+	dl_tbf->direction = GPRS_RLCMAC_DL_TBF;
+	ul_tbf = talloc_zero(tall_pcu_ctx, struct gprs_rlcmac_ul_tbf);
+	ul_tbf->direction = GPRS_RLCMAC_UL_TBF;
+
+	OSMO_ASSERT(last_cb == UNKNOWN);
+
+	ms->attach_tbf(ul_tbf);
+	OSMO_ASSERT(!ms->is_idle());
+	OSMO_ASSERT(last_cb == IS_ACTIVE);
+
+	last_cb = UNKNOWN;
+
+	ms->attach_tbf(dl_tbf);
+	OSMO_ASSERT(!ms->is_idle());
+	OSMO_ASSERT(last_cb == UNKNOWN);
+
+	ms->detach_tbf(ul_tbf);
+	OSMO_ASSERT(!ms->is_idle());
+	OSMO_ASSERT(last_cb == UNKNOWN);
+
+	ms->detach_tbf(dl_tbf);
+	OSMO_ASSERT(!ms->is_idle());
+	OSMO_ASSERT(last_cb == UNKNOWN);
+
+	usleep(1100000);
+	osmo_timers_update();
+
+	OSMO_ASSERT(ms->is_idle());
+	OSMO_ASSERT(last_cb == IS_IDLE);
+
+	last_cb = UNKNOWN;
+	delete ms;
+	talloc_free(dl_tbf);
+	talloc_free(ul_tbf);
+
+	printf("=== end %s ===\n", __func__);
+}
+
 static const struct log_info_cat default_categories[] = {
 	{"DPCU", "", "GPRS Packet Control Unit (PCU)", LOGL_INFO, 1},
 };
@@ -437,6 +506,7 @@ int main(int argc, char **argv)
 	test_ms_replace_tbf();
 	test_ms_change_tlli();
 	test_ms_storage();
+	test_ms_timeout();
 
 	if (getenv("TALLOC_REPORT_FULL"))
 		talloc_report_full(tall_pcu_ctx, stderr);

tests/ms/MsTest.err

@@ -47,3 +47,10 @@ Destroying MS object, TLLI = 0xffeeddbb
 Attaching TBF to MS object, TLLI = 0xffeeddbc, TBF = TBF(TFI=0 TLLI=0x00000000 DIR=UL STATE=NULL)
 Detaching TBF from MS object, TLLI = 0xffeeddbc, TBF = TBF(TFI=0 TLLI=0x00000000 DIR=UL STATE=NULL)
 Destroying MS object, TLLI = 0xffeeddbc
+Creating MS object, TLLI = 0xffeeddbb
+Attaching TBF to MS object, TLLI = 0xffeeddbb, TBF = TBF(TFI=0 TLLI=0x00000000 DIR=UL STATE=NULL)
+Attaching TBF to MS object, TLLI = 0xffeeddbb, TBF = TBF(TFI=0 TLLI=0x00000000 DIR=DL STATE=NULL)
+Detaching TBF from MS object, TLLI = 0xffeeddbb, TBF = TBF(TFI=0 TLLI=0x00000000 DIR=UL STATE=NULL)
+Detaching TBF from MS object, TLLI = 0xffeeddbb, TBF = TBF(TFI=0 TLLI=0x00000000 DIR=DL STATE=NULL)
+Timeout for MS object, TLLI = 0xffeeddbb
+Destroying MS object, TLLI = 0xffeeddbb

tests/ms/MsTest.ok

@@ -12,3 +12,7 @@
 === end test_ms_change_tlli ===
 === start test_ms_storage ===
 === end test_ms_storage ===
+=== start test_ms_timeout ===
+  ms_active() was called
+  ms_idle() was called
+=== end test_ms_timeout ===