gsm0808: Add utils for Cell Identifier List
The planned support for true A over IP requires the encoding of
the a Cell Identifier List element (see also BSS_MAP_MSG_PAGING).
This commt adds encoding/decoding functionality and tests for
the element mentioned above, however, it is not yet actively used.
Change-Id: I625245dd1dd396fc2bc189e8cd2c444a33042528
diff --git a/src/gsm/gsm0808_utils.c b/src/gsm/gsm0808_utils.c
index 1915605..054372a 100644
--- a/src/gsm/gsm0808_utils.c
+++ b/src/gsm/gsm0808_utils.c
@@ -450,3 +450,81 @@
return (int)(elem - old_elem);
}
+
+/* Encode Cell Identifier List element */
+uint8_t gsm0808_enc_cell_id_list(struct msgb *msg,
+ const struct gsm0808_cell_id_list *cil)
+{
+ uint8_t *old_tail;
+ uint8_t *tlv_len;
+ unsigned int i;
+
+ OSMO_ASSERT(msg);
+ OSMO_ASSERT(cil);
+
+ msgb_put_u8(msg, GSM0808_IE_CELL_IDENTIFIER_LIST);
+ tlv_len = msgb_put(msg, 1);
+ old_tail = msg->tail;
+
+ msgb_put_u8(msg, cil->id_discr & 0x0f);
+
+ switch (cil->id_discr) {
+ case CELL_IDENT_LAC:
+ OSMO_ASSERT(cil->id_list_len <= CELL_ID_LIST_LAC_MAXLEN)
+ for (i=0;i<cil->id_list_len;i++) {
+ msgb_put_u16(msg, cil->id_list_lac[i]);
+ }
+ break;
+ case CELL_IDENT_BSS:
+ /* Does not have any list items */
+ break;
+ default:
+ /* FIXME: Implement support for all identifier list elements */
+ OSMO_ASSERT(false);
+ }
+
+ *tlv_len = (uint8_t) (msg->tail - old_tail);
+ return *tlv_len + 2;
+}
+
+/* Decode Cell Identifier List element */
+int gsm0808_dec_cell_id_list(struct gsm0808_cell_id_list *cil,
+ const uint8_t *elem, uint8_t len)
+{
+ uint8_t id_discr;
+ const uint8_t *old_elem = elem;
+ unsigned int item_count = 0;
+
+ OSMO_ASSERT(cil);
+ if (!elem)
+ return -EINVAL;
+ if (len <= 0)
+ return -EINVAL;
+
+ memset(cil, 0, sizeof(*cil));
+
+ id_discr = *elem & 0x0f;
+ elem++;
+ len--;
+
+ cil->id_discr = id_discr;
+
+ switch (id_discr) {
+ case CELL_IDENT_LAC:
+ while (len >= 2) {
+ cil->id_list_lac[item_count] = osmo_load16be(elem);
+ elem += 2;
+ item_count++;
+ len -= 2;
+ }
+ case CELL_IDENT_BSS:
+ /* Does not have any list items */
+ break;
+ default:
+ /* FIXME: Implement support for all identifier list elements */
+ return -EINVAL;
+ }
+
+ cil->id_list_len = item_count;
+ return (int)(elem - old_elem);
+}
diff --git a/src/gsm/libosmogsm.map b/src/gsm/libosmogsm.map
index 323ad5a..cf0a7fe 100644
--- a/src/gsm/libosmogsm.map
+++ b/src/gsm/libosmogsm.map
@@ -150,6 +150,8 @@
gsm0808_dec_channel_type;
gsm0808_enc_encrypt_info;
gsm0808_dec_encrypt_info;
+gsm0808_enc_cell_id_list;
+gsm0808_dec_cell_id_list;
gsm0858_rsl_ul_meas_enc;