diff options
authorJacob Erlbeck <jerlbeck@sysmocom.de>2015-09-01 11:28:25 +0200
committerJacob Erlbeck <jerlbeck@sysmocom.de>2015-09-01 12:00:31 +0200
commitae0a799f4472a75912b444cc2f09361aaea27963 (patch)
parent91ff7d1864f0248ab5f45047069c09d7843212ca (diff)
bts: Release DL TBF instead of killing in rcv_resource_request
Currently an existing DL TBF is freed immediately, when a resource request is received. This makes sense since the MS might have dropped it when switching to the PDCH signaled via the AGCH for the SBA. But if the TBF still is assumed to exist on the MS side, there might be TFI collisions if the old TBF object is not kept to block its TFI for some time. This commit changes rcv_resource_request to call release() instead of tbf_free() on the DL TBF object (if it exists). Sponsored-by: On-Waves ehf
2 files changed, 12 insertions, 9 deletions
diff --git a/src/bts.cpp b/src/bts.cpp
index 98a23cc..6528915 100644
--- a/src/bts.cpp
+++ b/src/bts.cpp
@@ -984,17 +984,23 @@ void gprs_rlcmac_pdch::rcv_resource_request(Packet_Resource_Request_t *request,
"TLLI=0x%08x while %s still "
"exists. Killing pending UL TBF\n",
tlli, tbf_name(ul_tbf));
+ /* The MS will not use the old TBF again, so we can
+ * safely throw it away immediately */
ul_tbf = NULL;
if (dl_tbf) {
+ /* TODO: There a chance that releasing dl_tbf can be
+ * avoided if this PDCH is the control TS of dl_tbf,
+ * but this needs to be checked with the spec. If an MS
+ * losed the DL TBF because of PDCH mismatches only,
+ * this check would make sense. */
"TLLI=0x%08x while %s still exists. "
- "Killing pending DL TBF\n", tlli,
+ "Release pending DL TBF\n", tlli,
- tbf_free(dl_tbf);
- dl_tbf = NULL;
+ dl_tbf->release();
"in packet resource request of single "
diff --git a/tests/tbf/TbfTest.err b/tests/tbf/TbfTest.err
index 024e2d8..8401e08 100644
--- a/tests/tbf/TbfTest.err
+++ b/tests/tbf/TbfTest.err
@@ -1792,12 +1792,9 @@ Searching for first unallocated TFI: TRX=0
Found TFI=0.
+++++++++++++++++++++++++ RX : Uplink Control Block +++++++++++++++++++++++++
------------------------- RX : Uplink Control Block -------------------------
-Got RACH from TLLI=0xf1223344 while TBF(TFI=0 TLLI=0xf1223344 DIR=DL STATE=ASSIGN) still exists. Killing pending DL TBF
-TBF(TFI=0 TLLI=0xf1223344 DIR=DL STATE=ASSIGN) free
-TBF(TFI=0 TLLI=0xf1223344 DIR=DL STATE=ASSIGN) stopping timer 0.
-PDCH(TS 7, TRX 0): Detaching TBF(TFI=0 TLLI=0xf1223344 DIR=DL STATE=ASSIGN), 0 TBFs, USFs = 00, TFIs = 00000000.
-Detaching TBF from MS object, TLLI = 0xf1223344, TBF = TBF(TFI=0 TLLI=0xf1223344 DIR=DL STATE=ASSIGN)
-********** TBF ends here **********
+Got RACH from TLLI=0xf1223344 while TBF(TFI=0 TLLI=0xf1223344 DIR=DL STATE=ASSIGN) still exists. Release pending DL TBF
+TBF(TFI=0 TLLI=0xf1223344 DIR=DL STATE=ASSIGN) changes state from ASSIGN to WAIT RELEASE
+TBF(TFI=0 TLLI=0xf1223344 DIR=DL STATE=WAIT RELEASE) restarting timer 3193 while old timer 0 pending
MS requests UL TBF in packet resource request of single block, so we provide one:
********** TBF starts here **********
Allocating UL TBF: MS_CLASS=1