bsc: Work on paging and parsing other messages

The paging is not implemented due bad/missing API in the
BSC API, the rest are simple stubs to be merged from the
on-waves/bsc-master.

1 files changed, 140 insertions, 1 deletions

diff --git a/openbsc/src/bsc/osmo_bsc_bssap.c b/openbsc/src/bsc/osmo_bsc_bssap.c
index 44c652bbd..6ca535bd0 100644
--- a/openbsc/src/bsc/osmo_bsc_bssap.c
+++ b/openbsc/src/bsc/osmo_bsc_bssap.c
@@ -20,10 +20,132 @@
  */
 
 #include <openbsc/osmo_bsc.h>
+#include <openbsc/osmo_bsc_grace.h>
 #include <openbsc/debug.h>
 
+#include <osmocore/gsm0808.h>
 #include <osmocore/protocol/gsm_08_08.h>
 
+#include <arpa/inet.h>
+
+static uint16_t read_data16(const uint8_t *data)
+{
+	uint16_t res;
+
+	memcpy(&res, data, sizeof(res));
+	return res;
+}
+
+static int bssmap_handle_reset_ack(struct gsm_network *net,
+				   struct msgb *msg, unsigned int length)
+{
+	LOGP(DMSC, LOGL_NOTICE, "Reset ACK from MSC\n");
+	return 0;
+}
+
+/* GSM 08.08 § 3.2.1.19 */
+static int bssmap_handle_paging(struct gsm_network *net,
+				struct msgb *msg, unsigned int payload_length)
+{
+	struct tlv_parsed tp;
+	char mi_string[GSM48_MI_SIZE];
+	uint32_t tmsi = GSM_RESERVED_TMSI;
+	unsigned int lac = GSM_LAC_RESERVED_ALL_BTS;
+	uint8_t data_length;
+	const uint8_t *data;
+	uint8_t chan_needed = RSL_CHANNEED_ANY;
+
+	tlv_parse(&tp, gsm0808_att_tlvdef(), msg->l4h + 1, payload_length - 1, 0, 0);
+
+	if (!TLVP_PRESENT(&tp, GSM0808_IE_IMSI)) {
+		LOGP(DMSC, LOGL_ERROR, "Mandantory IMSI not present.\n");
+		return -1;
+	} else if ((TLVP_VAL(&tp, GSM0808_IE_IMSI)[0] & GSM_MI_TYPE_MASK) != GSM_MI_TYPE_IMSI) {
+		LOGP(DMSC, LOGL_ERROR, "Wrong content in the IMSI\n");
+		return -1;
+	}
+
+	if (!TLVP_PRESENT(&tp, GSM0808_IE_CELL_IDENTIFIER_LIST)) {
+		LOGP(DMSC, LOGL_ERROR, "Mandantory CELL IDENTIFIER LIST not present.\n");
+		return -1;
+	}
+
+	if (TLVP_PRESENT(&tp, GSM0808_IE_TMSI)) {
+		gsm48_mi_to_string(mi_string, sizeof(mi_string),
+			   TLVP_VAL(&tp, GSM0808_IE_TMSI), TLVP_LEN(&tp, GSM0808_IE_TMSI));
+		tmsi = strtoul(mi_string, NULL, 10);
+	}
+
+
+	/*
+	 * parse the IMSI
+	 */
+	gsm48_mi_to_string(mi_string, sizeof(mi_string),
+			   TLVP_VAL(&tp, GSM0808_IE_IMSI), TLVP_LEN(&tp, GSM0808_IE_IMSI));
+
+	/*
+	 * parse the cell identifier list
+	 */
+	data_length = TLVP_LEN(&tp, GSM0808_IE_CELL_IDENTIFIER_LIST);
+	data = TLVP_VAL(&tp, GSM0808_IE_CELL_IDENTIFIER_LIST);
+
+	/*
+	 * Support paging to all network or one BTS at one LAC
+	 */
+	if (data_length == 3 && data[0] == CELL_IDENT_LAC) {
+		lac = ntohs(read_data16(&data[1]));
+	} else if (data_length > 1 || (data[0] & 0x0f) != CELL_IDENT_BSS) {
+		LOGP(DMSC, LOGL_ERROR, "Unsupported Cell Identifier List: %s\n", hexdump(data, data_length));
+		return -1;
+	}
+
+	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;
+
+	if (TLVP_PRESENT(&tp, GSM0808_IE_EMLPP_PRIORITY)) {
+		LOGP(DMSC, LOGL_ERROR, "eMLPP is not handled\n");
+	}
+
+	LOGP(DMSC, LOGL_DEBUG, "Paging request from MSC IMSI: '%s' TMSI: '0x%x/%u' LAC: 0x%x\n", mi_string, tmsi, tmsi, lac);
+	LOGP(DMSC, LOGL_ERROR, "Paging is not implemented...\n");
+	return -1;
+}
+
+static int bssmap_rcvmsg_udt(struct gsm_network *net,
+			     struct msgb *msg, unsigned int length)
+{
+	int ret = 0;
+
+	if (length < 1) {
+		LOGP(DMSC, LOGL_ERROR, "Not enough room: %d\n", length);
+		return -1;
+	}
+
+	switch (msg->l4h[0]) {
+	case BSS_MAP_MSG_RESET_ACKNOWLEDGE:
+		ret = bssmap_handle_reset_ack(net, msg, length);
+		break;
+	case BSS_MAP_MSG_PAGING:
+		if (bsc_grace_allow_new_connection(net))
+			ret = bssmap_handle_paging(net, msg, length);
+		break;
+	}
+
+	return ret;
+}
+
+static int bssmap_rcvmsg_dt1(struct osmo_bsc_sccp_con *conn,
+			     struct msgb *msg, unsigned int length)
+{
+	return -1;
+}
+
+static int dtap_rcvmsg(struct osmo_bsc_sccp_con *conn,
+		       struct msgb *msg, unsigned int length)
+{
+	return -1;
+}
+
 int bsc_handle_udt(struct gsm_network *network,
 		   struct bsc_msc_connection *conn,
 		   struct msgb *msgb, unsigned int length)
@@ -44,7 +166,8 @@ int bsc_handle_udt(struct gsm_network *network,
 
 	switch (bs->type) {
 	case BSSAP_MSG_BSS_MANAGEMENT:
-		LOGP(DMSC, LOGL_ERROR, "BSS management not implemented.\n");
+		msgb->l4h = &msgb->l3h[sizeof(*bs)];
+		bssmap_rcvmsg_udt(network, msgb, length - sizeof(*bs));
 		break;
 	default:
 		LOGP(DMSC, LOGL_ERROR, "Unimplemented msg type: %d\n", bs->type);
@@ -56,5 +179,21 @@ int bsc_handle_udt(struct gsm_network *network,
 int bsc_handle_dt1(struct osmo_bsc_sccp_con *conn,
 		   struct msgb *msg, unsigned int len)
 {
+	if (len < sizeof(struct bssmap_header)) {
+		LOGP(DMSC, LOGL_ERROR, "The header is too short.\n");
+	}
+
+	switch (msg->l3h[0]) {
+	case BSSAP_MSG_BSS_MANAGEMENT:
+		msg->l4h = &msg->l3h[sizeof(struct bssmap_header)];
+		bssmap_rcvmsg_dt1(conn, msg, len - sizeof(struct bssmap_header));
+		break;
+	case BSSAP_MSG_DTAP:
+		dtap_rcvmsg(conn, msg, len);
+		break;
+	default:
+		LOGP(DMSC, LOGL_DEBUG, "Unimplemented msg type: %d\n", msg->l3h[0]);
+	}
+
 	return -1;
 }