use libosmocore to parse cell identifiers in osmo-bsc

This replaces custom cell identifier parsing in the paging code with
calls to the new cell identifier parser implementation in libosmocore
(which was derived from the code that is now being replaced here).

The bssap tests will fail unless this other change is merged to
libosmocore as well: https://gerrit.osmocom.org/#/c/7288/

Related: OS#2847
Change-Id: I9e2002fbbe135287e9ce09caa3f0a85a84529463
Depends: I7f3e8ace26176e9cbfe2542961d2a95662aa4d97

1 files changed, 49 insertions, 86 deletions

diff --git a/src/osmo-bsc/osmo_bsc_bssap.c b/src/osmo-bsc/osmo_bsc_bssap.c
index db749a3da..176a41374 100644
--- a/src/osmo-bsc/osmo_bsc_bssap.c
+++ b/src/osmo-bsc/osmo_bsc_bssap.c
@@ -260,18 +260,6 @@ page_subscriber(struct bsc_msc_data *msc, struct gsm_bts *bts,
 	return ret;
 }
 
-/* Decode 5-byte LAI list element data (see TS 08.08 3.2.2.27) into MCC/MNC/LAC.
- * Return 0 if successful, negative on error. */
-static void
-decode_lai(const uint8_t *data, struct osmo_location_area_id *laid)
-{
-	struct gsm48_loc_area_id lai;
-
-	/* Copy data to stack to prevent unaligned access in gsm48_decode_lai(). */
-	memcpy(&lai, data, sizeof(lai)); /* don't byte swap yet */
-	gsm48_decode_lai2(&lai, laid);
-}
-
 static void
 page_all_bts(struct bsc_msc_data *msc, uint32_t tmsi, const char *mi_string, uint8_t chan_needed)
 {
@@ -283,83 +271,71 @@ page_all_bts(struct bsc_msc_data *msc, uint32_t tmsi, const char *mi_string, uin
 }
 
 static void
-page_cgi(struct bsc_msc_data *msc, const uint8_t *data, uint8_t data_length, size_t remain,
+page_cgi(struct bsc_msc_data *msc, struct gsm0808_cell_id_list2 *cil,
 	 uint32_t tmsi, const char *mi_string, uint8_t chan_needed)
 {
-	uint16_t ci;
-	int i = 0;
-	while (remain >= sizeof(struct gsm48_loc_area_id) + sizeof(ci)) {
-		struct osmo_location_area_id lai;
-		uint16_t *ci_be;
-		size_t lai_offset = 1 + i * (sizeof(struct gsm48_loc_area_id) + sizeof(ci));
-		decode_lai(&data[lai_offset], &lai);
-		ci_be = (uint16_t *)(&data[lai_offset + sizeof(struct gsm48_loc_area_id)]);
-		ci = osmo_load16be(ci_be);
-		if (!osmo_plmn_cmp(&lai.plmn, &msc->network->plmn)) {
+	int i;
+	for (i = 0; i < cil->id_list_len; i++) {
+		struct osmo_cell_global_id *id = &cil->id_list[i].global;
+		if (!osmo_plmn_cmp(&id->lai.plmn, &msc->network->plmn)) {
 			int paged = 0;
 			struct gsm_bts *bts;
 			llist_for_each_entry(bts, &msc->network->bts_list, list) {
-				if (bts->location_area_code != lai.lac)
+				if (bts->location_area_code != id->lai.lac)
 					continue;
-				if (bts->cell_identity != ci)
+				if (bts->cell_identity != id->cell_identity)
 					continue;
 				/* ignore errors from page_subscriber(); keep trying other BTS */
-				page_subscriber(msc, bts, tmsi, lai.lac, mi_string, chan_needed);
+				page_subscriber(msc, bts, tmsi, id->lai.lac, mi_string, chan_needed);
 				paged = 1;
 			}
 			if (!paged) {
 				LOGP(DMSC, LOGL_NOTICE, "Paging IMSI %s: BTS with LAC %d and CI %d not found\n",
-				     mi_string, lai.lac, ci);
+				     mi_string, id->lai.lac, id->cell_identity);
 			}
 		} else {
 			LOGP(DMSC, LOGL_DEBUG, "Paging IMSI %s: MCC-MNC in Cell Identifier List "
 			     "(%s) do not match our network (%s)\n",
-			     mi_string, osmo_plmn_name(&lai.plmn),
+			     mi_string, osmo_plmn_name(&id->lai.plmn),
 			     osmo_plmn_name2(&msc->network->plmn));
 		}
-		remain -= sizeof(struct gsm48_loc_area_id) + sizeof(ci);
-		i++;
 	}
 }
 
 static void
-page_lac_and_ci(struct bsc_msc_data *msc, const uint8_t *data, size_t remain,
+page_lac_and_ci(struct bsc_msc_data *msc, struct gsm0808_cell_id_list2 *cil,
 	 uint32_t tmsi, const char *mi_string, uint8_t chan_needed)
 {
-	uint16_t *lacp_be, *ci_be;
-	lacp_be = (uint16_t *)(&data[1]);
-	ci_be = (uint16_t *)(&data[3]);
-	while (remain >= sizeof(*lacp_be) + sizeof(*ci_be)) {
-		uint16_t lac = osmo_load16be(lacp_be);
-		uint16_t ci = osmo_load16be(ci_be);
+	int i;
+
+	for (i = 0; i < cil->id_list_len; i++) {
+		struct osmo_lac_and_ci_id *id = &cil->id_list[i].lac_and_ci;
 		int paged = 0;
 		struct gsm_bts *bts;
 		llist_for_each_entry(bts, &msc->network->bts_list, list) {
-			if (bts->location_area_code != lac)
+			if (bts->location_area_code != id->lac)
 				continue;
-			if (bts->cell_identity != ci)
+			if (bts->cell_identity != id->ci)
 				continue;
 			/* ignore errors from page_subscriber(); keep trying other BTS */
-			page_subscriber(msc, bts, tmsi, lac, mi_string, chan_needed);
+			page_subscriber(msc, bts, tmsi, id->lac, mi_string, chan_needed);
 			paged = 1;
 		}
 		if (!paged) {
 			LOGP(DMSC, LOGL_NOTICE, "Paging IMSI %s: BTS with LAC %d and CI %d not found\n",
-			     mi_string, lac, ci);
+			     mi_string, id->lac, id->ci);
 		}
-		remain -= sizeof(*lacp_be) + sizeof(*ci_be);
-		lacp_be++;
-		ci_be++;
 	}
 }
 
 static void
-page_ci(struct bsc_msc_data *msc, const uint8_t *data, size_t remain,
+page_ci(struct bsc_msc_data *msc, struct gsm0808_cell_id_list2 *cil,
 	 uint32_t tmsi, const char *mi_string, uint8_t chan_needed)
 {
-	uint16_t *ci_be = (uint16_t *)(&data[1]);
-	while (remain >= sizeof(*ci_be)) {
-		uint16_t ci = osmo_load16be(ci_be);
+	int i;
+
+	for (i = 0; i < cil->id_list_len; i++) {
+		uint16_t ci = cil->id_list[i].ci;
 		int paged = 0;
 		struct gsm_bts *bts;
 		llist_for_each_entry(bts, &msc->network->bts_list, list) {
@@ -373,51 +349,48 @@ page_ci(struct bsc_msc_data *msc, const uint8_t *data, size_t remain,
 			LOGP(DMSC, LOGL_NOTICE, "Paging IMSI %s: BTS with CI %d not found\n",
 			     mi_string, ci);
 		}
-		remain -= sizeof(*ci_be);
-		ci_be++;
 	}
 }
 
 static void
-page_lai_and_lac(struct bsc_msc_data *msc, const uint8_t *data, size_t data_length, size_t remain,
+page_lai_and_lac(struct bsc_msc_data *msc, struct gsm0808_cell_id_list2 *cil,
 	 uint32_t tmsi, const char *mi_string, uint8_t chan_needed)
 {
-	int i = 0;
-	while (remain >= sizeof(struct gsm48_loc_area_id)) {
-		struct osmo_location_area_id lai;
-		decode_lai(&data[1 + i * sizeof(struct gsm48_loc_area_id)], &lai);
-		if (!osmo_plmn_cmp(&lai.plmn, &msc->network->plmn)) {
+	int i;
+
+	for (i = 0; i < cil->id_list_len; i++) {
+		struct osmo_location_area_id *id = &cil->id_list[i].lai_and_lac;
+		if (!osmo_plmn_cmp(&id->plmn, &msc->network->plmn)) {
 			int paged = 0;
 			struct gsm_bts *bts;
 			llist_for_each_entry(bts, &msc->network->bts_list, list) {
-				if (bts->location_area_code != lai.lac)
+				if (bts->location_area_code != id->lac)
 					continue;
 				/* ignore errors from page_subscriber(); keep trying other BTS */
-				page_subscriber(msc, bts, tmsi, lai.lac, mi_string, chan_needed);
+				page_subscriber(msc, bts, tmsi, id->lac, mi_string, chan_needed);
 				paged = 1;
 			}
 			if (!paged) {
 				LOGP(DMSC, LOGL_NOTICE, "Paging IMSI %s: BTS with LAC %d not found\n",
-				     mi_string, lai.lac);
+				     mi_string, id->lac);
 			}
 		} else {
 			LOGP(DMSC, LOGL_DEBUG, "Paging IMSI %s: MCC-MNC in Cell Identifier List "
 			     "(%s) do not match our network (%s)\n",
-			     mi_string, osmo_plmn_name(&lai.plmn),
+			     mi_string, osmo_plmn_name(&id->plmn),
 			     osmo_plmn_name2(&msc->network->plmn));
 		}
-		remain -= sizeof(struct gsm48_loc_area_id);
-		i++;
 	}
 }
 
 static void
-page_lac(struct bsc_msc_data *msc, const uint8_t *data, size_t remain,
+page_lac(struct bsc_msc_data *msc, struct gsm0808_cell_id_list2 *cil,
 	 uint32_t tmsi, const char *mi_string, uint8_t chan_needed)
 {
-	uint16_t *lacp_be = (uint16_t *)(&data[1]);
-	while (remain >= sizeof(*lacp_be)) {
-		uint16_t lac = osmo_load16be(lacp_be);
+	int i;
+
+	for (i = 0; i < cil->id_list_len; i++) {
+		uint16_t lac = cil->id_list[i].lac;
 		int paged = 0;
 		struct gsm_bts *bts;
 		llist_for_each_entry(bts, &msc->network->bts_list, list) {
@@ -431,8 +404,6 @@ page_lac(struct bsc_msc_data *msc, const uint8_t *data, size_t remain,
 			LOGP(DMSC, LOGL_NOTICE, "Paging IMSI %s: BTS with LAC %d not found\n",
 			     mi_string, lac);
 		}
-		remain -= sizeof(*lacp_be);
-		lacp_be++;
 	}
 }
 
@@ -447,7 +418,7 @@ static int bssmap_handle_paging(struct bsc_msc_data *msc,
 	int remain;
 	const uint8_t *data;
 	uint8_t chan_needed = RSL_CHANNEED_ANY;
-	uint8_t cell_ident;
+	struct gsm0808_cell_id_list2 cil;
 
 	tlv_parse(&tp, gsm0808_att_tlvdef(), msg->l4h + 1, payload_length - 1, 0, 0);
 	remain = payload_length - 1;
@@ -490,17 +461,12 @@ static int bssmap_handle_paging(struct bsc_msc_data *msc,
 	 */
 	data_length = TLVP_LEN(&tp, GSM0808_IE_CELL_IDENTIFIER_LIST);
 	data = TLVP_VAL(&tp, GSM0808_IE_CELL_IDENTIFIER_LIST);
-
-	if (data_length < 1) {
-		LOGP(DMSC, LOGL_ERROR, "Paging IMSI %s: Zero length Cell Identifier List\n",
-		     mi_string);
-		return -1;
-	} else if (data_length > remain) {
+	if (gsm0808_dec_cell_id_list2(&cil, data, data_length) < 0) {
 		LOGP(DMSC, LOGL_ERROR, "Paging IMSI %s: Bogus Cell Identifier List length\n",
 		     mi_string);
 		return -1;
 	}
-	remain = data_length; /* ignore payload padding data beyond data_length */
+	remain = 0;
 
 	if (TLVP_PRESENT(&tp, GSM0808_IE_CHANNEL_NEEDED) && TLVP_LEN(&tp, GSM0808_IE_CHANNEL_NEEDED) == 1)
 		chan_needed = TLVP_VAL(&tp, GSM0808_IE_CHANNEL_NEEDED)[0] & 0x03;
@@ -509,34 +475,31 @@ static int bssmap_handle_paging(struct bsc_msc_data *msc,
 		LOGP(DMSC, LOGL_ERROR, "eMLPP is not handled\n");
 	}
 
-	cell_ident = data[0] & 0xf;
-	remain -= 1; /* cell ident consumed */
-
 	rate_ctr_inc(&msc->network->bsc_ctrs->ctr[BSC_CTR_PAGING_ATTEMPTED]);
 
-	switch (cell_ident) {
+	switch (cil.id_discr) {
 	case CELL_IDENT_NO_CELL:
 		page_all_bts(msc, tmsi, mi_string, chan_needed);
 		break;
 
 	case CELL_IDENT_WHOLE_GLOBAL:
-		page_cgi(msc, data, data_length, remain, tmsi, mi_string, chan_needed);
+		page_cgi(msc, &cil, tmsi, mi_string, chan_needed);
 		break;
 
 	case CELL_IDENT_LAC_AND_CI:
-		page_lac_and_ci(msc, data, remain, tmsi, mi_string, chan_needed);
+		page_lac_and_ci(msc, &cil, tmsi, mi_string, chan_needed);
 		break;
 
 	case CELL_IDENT_CI:
-		page_ci(msc, data, remain, tmsi, mi_string, chan_needed);
+		page_ci(msc, &cil, tmsi, mi_string, chan_needed);
 		break;
 
 	case CELL_IDENT_LAI_AND_LAC:
-		page_lai_and_lac(msc, data, data_length, remain, tmsi, mi_string, chan_needed);
+		page_lai_and_lac(msc, &cil, tmsi, mi_string, chan_needed);
 		break;
 
 	case CELL_IDENT_LAC:
-		page_lac(msc, data, remain, tmsi, mi_string, chan_needed);
+		page_lac(msc, &cil, tmsi, mi_string, chan_needed);
 		break;
 
 	case CELL_IDENT_BSS:
@@ -551,7 +514,7 @@ static int bssmap_handle_paging(struct bsc_msc_data *msc,
 	default:
 		LOGP(DMSC, LOGL_NOTICE, "Paging IMSI %s: unimplemented Cell Identifier List (0x%x),"
 		     " paging entire BSS instead (%s)\n",
-		     mi_string, cell_ident, osmo_hexdump(data, data_length));
+		     mi_string, cil.id_discr, osmo_hexdump(data, data_length));
 		page_all_bts(msc, tmsi, mi_string, chan_needed);
 		break;
 	}