BTS_Tests: fix expectations in TC_speech_no_rtp_tch[fh]
This testcase is currently passing for both -master and -latest
versions of osmo-bts, despite their behavior is different:
* the -latest is sending FACCH frames with dummy LAPDm func=UI,
* the -master is sending invalid speech frames with inverted CRC3.
There is a bug in the 'tr_bad_frame' template definition: we expect
the payload to be present, while in real BFIs it's omitted. So these
two testcases would always pass, even if the IUT would be sending dummy
bursts or sending nothing at all, because they were designed to fail on
receipt of a never-matching TRAFFIC.ind template.
Let's fix this and align our expectations with the current behavior
of the -master version of osmo-bts. Note that sending invalid speech
frames with inverted CRC3 is not osmo-bts-trx specific behavior;
it's actually a replicated behavior of DSP based osmo-bts-sysmo.
Change-Id: Ic680002f60e598cfeeb448c517581b3506355e5b
Related: osmo-bts.git I78106802a0aa4af39859c75d29fe0e77037899fe
Related: SYS#5919, OS#4823
diff --git a/bts/BTS_Tests.ttcn b/bts/BTS_Tests.ttcn
index 3433666..5a34a8c 100644
--- a/bts/BTS_Tests.ttcn
+++ b/bts/BTS_Tests.ttcn
@@ -8235,7 +8235,8 @@
}
private function f_TC_speech_no_rtp(charstring id) runs on ConnHdlr {
- var template L1ctlMessage tr_bad_frame;
+ var template L1ctlMessage tr_dummy_frame;
+ var integer dummy_frame_num := 0;
var L1ctlMessage l1_dl;
timer T := 8.0;
@@ -8248,24 +8249,30 @@
f_sleep(2.0); /* ... so let's give the L1 some time to stabilize */
L1CTL.clear;
- /* A universal template for bad Downlink frame: {DATA,TRAFFIC}.ind */
- tr_bad_frame := tr_L1CTL_TRAFFIC_IND(g_chan_nr, tr_RslLinkID_DCCH(0));
- tr_bad_frame.header.msg_type := (L1CTL_DATA_IND, L1CTL_TRAFFIC_IND);
- tr_bad_frame.dl_info.fire_crc := (1..255); /* != 0 */
- tr_bad_frame.payload := ?;
+ /* Expect empty TRAFFIC.ind with no bit errors and bad CRC. In the absence
+ * of RTP, osmo-bts is transmitting dummy speech frames with inverted CRC3.
+ * This is a beautiful hack inducing a BFI condition in the MS receiver.
+ * See https://osmocom.org/issues/4823#note-13 for more details. */
+ tr_dummy_frame := tr_L1CTL_TRAFFIC_IND(g_chan_nr, tr_RslLinkID_DCCH(0));
+ tr_dummy_frame.dl_info.fire_crc := (1..255); /* != 0 */
+ tr_dummy_frame.dl_info.num_biterr := 0;
+ tr_dummy_frame.payload := omit;
T.start;
alt {
- /* OS#4823: DATA.ind or TRAFFIC.ind with bad CRC most likely means that
- * the IUT is sending *dummy bursts*, so the L1 fails to decode them. */
- [] L1CTL.receive(tr_bad_frame) -> value l1_dl {
- setverdict(fail, "Received {DATA,TRAFFIC}.ind with bad CRC: ", l1_dl);
+ [] L1CTL.receive(tr_dummy_frame) -> value l1_dl {
+ dummy_frame_num := dummy_frame_num + 1;
+ log("Rx dummy TRAFFIC.ind (num ", dummy_frame_num, "): ", l1_dl);
+ /* break the loop if we got 5 dummy frames */
+ if (dummy_frame_num < 5)
+ { repeat; }
+ }
+ [] L1CTL.receive(tr_L1CTL_TRAFFIC_IND(g_chan_nr)) -> value l1_dl {
+ setverdict(fail, "Rx unexpected TRAFFIC.ind: ", l1_dl);
}
[] as_l1_sacch();
- [] L1CTL.receive { repeat; }
[] T.timeout {
- /* We're done, break the loop */
- setverdict(pass);
+ setverdict(fail, "Timeout waiting for TRAFFIC.ind");
}
}