1 files changed, 104 insertions, 0 deletions
diff --git a/src/gprs_rlcmac.cpp b/src/gprs_rlcmac.cpp
index 2c87317..2ea0a61 100644
--- a/src/gprs_rlcmac.cpp
+++ b/src/gprs_rlcmac.cpp
@@ -1819,3 +1819,107 @@ int gprs_rlcmac_paging_request(uint8_t *ptmsi, uint16_t ptmsi_len,
 
 	return 0;
 }
+
+
+/*
+ * timing advance memory
+ */
+
+/* enable to debug timing advance memory */
+//#define DEBUG_TA
+
+static LLIST_HEAD(gprs_rlcmac_ta_list);
+static int gprs_rlcmac_ta_num = 0;
+
+struct gprs_rlcmac_ta {
+	struct llist_head	list;
+	uint32_t		tlli;
+	uint8_t			ta;
+};
+
+/* remember timing advance of a given TLLI */
+int remember_timing_advance(uint32_t tlli, uint8_t ta)
+{
+	struct gprs_rlcmac_ta *ta_entry;
+
+	/* check for existing entry */
+	llist_for_each_entry(ta_entry, &gprs_rlcmac_ta_list, list) {
+		if (ta_entry->tlli == tlli) {
+#ifdef DEBUG_TA
+			fprintf(stderr, "update %08x %d\n", tlli, ta);
+#endif
+			ta_entry->ta = ta;
+			/* relink to end of list */
+			llist_del(&ta_entry->list);
+			llist_add_tail(&ta_entry->list, &gprs_rlcmac_ta_list);
+			return 0;
+		}
+	}
+
+#ifdef DEBUG_TA
+	fprintf(stderr, "remember %08x %d\n", tlli, ta);
+#endif
+	/* if list is full, remove oldest entry */
+	if (gprs_rlcmac_ta_num == 30) {
+		ta_entry = llist_entry(gprs_rlcmac_ta_list.next,
+			struct gprs_rlcmac_ta, list);
+	        llist_del(&ta_entry->list);
+		talloc_free(ta_entry);
+		gprs_rlcmac_ta_num--;
+	}
+
+	/* create new TA entry */
+	ta_entry = talloc_zero(tall_pcu_ctx, struct gprs_rlcmac_ta);
+	if (!ta_entry)
+		return -ENOMEM;
+
+	ta_entry->tlli = tlli;
+	ta_entry->ta = ta;
+	llist_add_tail(&ta_entry->list, &gprs_rlcmac_ta_list);
+	gprs_rlcmac_ta_num++;
+
+	return 0;
+}
+
+int recall_timing_advance(uint32_t tlli)
+{
+	struct gprs_rlcmac_ta *ta_entry;
+	uint8_t ta;
+
+	llist_for_each_entry(ta_entry, &gprs_rlcmac_ta_list, list) {
+		if (ta_entry->tlli == tlli) {
+			ta = ta_entry->ta;
+#ifdef DEBUG_TA
+			fprintf(stderr, "recall %08x %d\n", tlli, ta);
+#endif
+			return ta;
+		}
+	}
+#ifdef DEBUG_TA
+	fprintf(stderr, "no entry for %08x\n", tlli);
+#endif
+
+	return -EINVAL;
+}
+
+int flush_timing_advance(void)
+{
+	struct gprs_rlcmac_ta *ta_entry;
+	int count = 0;
+
+	while (!llist_empty(&gprs_rlcmac_ta_list)) {
+		ta_entry = llist_entry(gprs_rlcmac_ta_list.next,
+			struct gprs_rlcmac_ta, list);
+#ifdef DEBUG_TA
+		fprintf(stderr, "flush entry %08x %d\n", ta_entry->tlli,
+			ta_entry->ta);
+#endif
+	        llist_del(&ta_entry->list);
+		talloc_free(ta_entry);
+		count++;
+	}
+	gprs_rlcmac_ta_num = 0;
+
+	return count;
+}
+