ms_need_dl_tbf(): Fix state checks and document function
A new state TBF_ST_WAIT_REUSE_TFI was added lately in dl_tbf_fsm, which
allows differentiating the time where the MS is listening on PACCH
after having sent last DL ACK/NACK, and time where it should already be
in idle mode.
In the former, the ms_need_dl_tbf() should return false since the MS is
still ongoing in packet-active mode (and new data incoming from SGSN
will trigger new DL TBF assignment over PACCH as needed), while in the
later we want to start a new PCH assignment.
Fixes: 40a297f3b0c8e1670d46a4974750dd3335bc7885
Change-Id: I96f311480d036859511c6ba825ccd36bdc71190b
diff --git a/src/gprs_ms.h b/src/gprs_ms.h
index ef1cc4e..276733c 100644
--- a/src/gprs_ms.h
+++ b/src/gprs_ms.h
@@ -157,11 +157,30 @@
return &ms->llc_queue;
}
+/* Function used in code where a ul_tbf related event occurs and hence its state
+ * changes, which in turn may change the entire MS state (eg becoming reachable
+ * over PCH or PACCH) and the caller may want to know if it is a good time to
+ * assign a DL TBF (and whether we have DL data to send) */
static inline bool ms_need_dl_tbf(struct GprsMs *ms)
{
- if (ms_dl_tbf(ms) != NULL &&
- tbf_state((const struct gprs_rlcmac_tbf *)ms_dl_tbf(ms)) != TBF_ST_WAIT_RELEASE)
- return false;
+ struct gprs_rlcmac_dl_tbf *dl_tbf = ms_dl_tbf(ms);
+ if (dl_tbf) {
+ switch (tbf_state(dl_tbf_as_tbf(dl_tbf))) {
+ case TBF_ST_NEW:
+ case TBF_ST_ASSIGN:
+ case TBF_ST_FLOW:
+ case TBF_ST_FINISHED:
+ case TBF_ST_WAIT_RELEASE:
+ return false; /* TBF in use, hence no need for new DL TBF */
+ case TBF_ST_WAIT_REUSE_TFI:
+ case TBF_ST_RELEASING:
+ /* TBF cannot be used to send further data, a new one
+ * may be needed, check below */
+ break;
+ default:
+ OSMO_ASSERT(0);
+ }
+ }
return llc_queue_size(ms_llc_queue(ms)) > 0;
}