tbf: Use TLLI as ID if TFI not yet assigned

Currently the old TFI is always used as ID when a
PACKET DOWNLINK ASSIGNMENT is generated. This fails
if the old TBF has not been fully assigned yet. The
MS will then ignore the PDA.

This commit changes write_packet_downlink_assignment to accept
an additional parameter old_tfi_is_valid and uses the new TBF's
TLLI instead of the olf TFI if that parameter is set to false.

Sponsored-by: On-Waves ehf

1 files changed, 11 insertions, 0 deletions

diff --git a/src/tbf.h b/src/tbf.h
index edb8280e..d1b286cb 100644
--- a/src/tbf.h
+++ b/src/tbf.h
@@ -132,6 +132,7 @@ struct gprs_rlcmac_tbf {
 	void update_ms(uint32_t tlli, enum gprs_rlcmac_tbf_direction);
 
 	uint8_t tfi() const;
+	bool is_tfi_assigned() const;
 
 	const char *imsi() const;
 	void assign_imsi(const char *imsi);
@@ -310,6 +311,16 @@ inline bool gprs_rlcmac_tbf::is_tlli_valid() const
 	return tlli() != 0;
 }
 
+inline bool gprs_rlcmac_tbf::is_tfi_assigned() const
+{
+	/* The TBF is established or has been assigned by a IMM.ASS for
+	 * download */
+	return state > GPRS_RLCMAC_ASSIGN ||
+		(direction == GPRS_RLCMAC_DL_TBF &&
+		 state == GPRS_RLCMAC_ASSIGN &&
+		 (state_flags & (1 << GPRS_RLCMAC_FLAG_CCCH)));
+}
+
 inline uint8_t gprs_rlcmac_tbf::tfi() const
 {
 	return m_tfi;