abis_rsl: Change code to generate Channel Identification
1.) memset the gsm48_chan_desc to avoid sending dummy data
2.) According to the GSM08.58 9.3.5 the Mobile Allocation
shall be included but the empty (by setting the length
to zero).
3.) use msgb_tlv_put and calculate the length via the l3h
msgb_l3len and assign it.
diff --git a/openbsc/src/abis_rsl.c b/openbsc/src/abis_rsl.c
index 7ca1de6..0a86e79 100644
--- a/openbsc/src/abis_rsl.c
+++ b/openbsc/src/abis_rsl.c
@@ -432,12 +432,12 @@
u_int8_t chan_nr = lchan2chan_nr(lchan);
struct rsl_ie_chan_mode cm;
struct gsm48_chan_desc cd;
- uint8_t *msgb_cd;
rc = channel_mode_from_lchan(&cm, lchan);
if (rc < 0)
return rc;
+ memset(&cd, 0, sizeof(cd));
gsm48_lchan2chan_desc(&cd, lchan);
msg = rsl_msgb_alloc();
@@ -448,26 +448,23 @@
msgb_tv_put(msg, RSL_IE_ACT_TYPE, act_type);
msgb_tlv_put(msg, RSL_IE_CHAN_MODE, sizeof(cm),
(u_int8_t *) &cm);
- /* For compatibility with Phase 1 */
- /* RSL IE TAG */
+
+ /*
+ * The Channel Identification is needed for Phase1 phones
+ * and it contains the GSM48 Channel Description and the
+ * Mobile Allocation. The GSM 08.58 asks for the Mobile
+ * Allocation to have a length of zero. We are using the
+ * msgb_l3len to calculate the length of both messages.
+ */
msgb_v_put(msg, RSL_IE_CHAN_IDENT);
- /* RSL IE LEN: 04.08_cd_tag + CD */
len = msgb_put(msg, 1);
- *len = 1 + sizeof(struct gsm48_chan_desc);
- msgb_v_put(msg, 1 + sizeof(struct gsm48_chan_desc) + 2 +
- lchan->ts->hopping.ma_len);
- /* GSM 04.08 Chan Desc 2 (TAG + fixed 3 byte length V) */
- msgb_v_put(msg, GSM48_IE_CHANDESC_2);
- msgb_cd = msgb_put(msg, sizeof(cd));
- memcpy(msgb_cd, &cd, sizeof(cd));
- if (lchan->ts->hopping.enabled) {
- /* RSL IE LEN: += 04.08_ma_tag + 04.08_ma_len + ma_len */
- *len += 2 + lchan->ts->hopping.ma_len;
- /* GSM 04.08 Mobile Allocation: TLV */
- msgb_tlv_put(msg, GSM48_IE_MA_AFTER, lchan->ts->hopping.ma_len,
- lchan->ts->hopping.ma_data);
- }
-
+ msgb_tlv_put(msg, GSM48_IE_CHANDESC_2, sizeof(cd), (const uint8_t *) &cd);
+ msgb_tlv_put(msg, GSM48_IE_MA_AFTER, 0, NULL);
+
+ /* update the calculated size */
+ msg->l3h = len + 1;
+ *len = msgb_l3len(msg);
+
if (lchan->encr.alg_id > RSL_ENC_ALG_A5(0)) {
u_int8_t encr_info[MAX_A5_KEY_LEN+2];
rc = build_encr_info(encr_info, lchan);