re-structure the OpenBSC directory layout

The new structure divides the code into a number of libraries
for the BSC core functionality, MSC core functionality, Abis transport,
TRAU and other bits.

This doesn't introduce any functional code change but simply moves
around files and alters Makefile.am accordingly.

Next step would be to disentangle a lot of the inter-library
dependencies and make the individual bits of code more independent.

1 files changed, 548 insertions, 0 deletions

diff --git a/openbsc/src/osmo-bsc/osmo_bsc_bssap.c b/openbsc/src/osmo-bsc/osmo_bsc_bssap.c
new file mode 100644
index 000000000..f8711314d
--- /dev/null
+++ b/openbsc/src/osmo-bsc/osmo_bsc_bssap.c
@@ -0,0 +1,548 @@
+/* GSM 08.08 BSSMAP handling						*/
+/* (C) 2009-2010 by Holger Hans Peter Freyther <zecke@selfish.org>
+ * (C) 2009-2010 by On-Waves
+ * All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include <openbsc/osmo_bsc.h>
+#include <openbsc/osmo_bsc_grace.h>
+#include <openbsc/osmo_msc_data.h>
+#include <openbsc/debug.h>
+#include <openbsc/gsm_subscriber.h>
+#include <openbsc/mgcp.h>
+#include <openbsc/paging.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;
+}
+
+/*
+ * helpers for the assignment command
+ */
+enum gsm0808_permitted_speech audio_support_to_gsm88(struct gsm_audio_support *audio)
+{
+	if (audio->hr) {
+		switch (audio->ver) {
+		case 1:
+			return GSM0808_PERM_HR1;
+			break;
+		case 2:
+			return GSM0808_PERM_HR2;
+			break;
+		case 3:
+			return GSM0808_PERM_HR3;
+			break;
+		default:
+			    LOGP(DMSC, LOGL_ERROR, "Wrong speech mode: %d\n", audio->ver);
+			    return GSM0808_PERM_FR1;
+		}
+	} else {
+		switch (audio->ver) {
+		case 1:
+			return GSM0808_PERM_FR1;
+			break;
+		case 2:
+			return GSM0808_PERM_FR2;
+			break;
+		case 3:
+			return GSM0808_PERM_FR3;
+			break;
+		default:
+			LOGP(DMSC, LOGL_ERROR, "Wrong speech mode: %d\n", audio->ver);
+			return GSM0808_PERM_HR1;
+		}
+	}
+}
+
+enum gsm48_chan_mode gsm88_to_chan_mode(enum gsm0808_permitted_speech speech)
+{
+	switch (speech) {
+	case GSM0808_PERM_HR1:
+	case GSM0808_PERM_FR1:
+		return GSM48_CMODE_SPEECH_V1;
+		break;
+	case GSM0808_PERM_HR2:
+	case GSM0808_PERM_FR2:
+		return GSM48_CMODE_SPEECH_EFR;
+		break;
+	case GSM0808_PERM_HR3:
+	case GSM0808_PERM_FR3:
+		return GSM48_CMODE_SPEECH_AMR;
+		break;
+	}
+
+	LOGP(DMSC, LOGL_FATAL, "Should not be reached.\n");
+	return GSM48_CMODE_SPEECH_AMR;
+}
+
+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 gsm_subscriber *subscr;
+	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");
+	}
+
+	subscr = subscr_get_or_create(net, mi_string);
+	if (!subscr) {
+		LOGP(DMSC, LOGL_ERROR, "Failed to allocate a subscriber for %s\n", mi_string);
+		return -1;
+	}
+
+	subscr->lac = lac;
+	subscr->tmsi = tmsi;
+
+	LOGP(DMSC, LOGL_DEBUG, "Paging request from MSC IMSI: '%s' TMSI: '0x%x/%u' LAC: 0x%x\n", mi_string, tmsi, tmsi, lac);
+	paging_request(net, subscr, chan_needed, NULL, NULL);
+	return 0;
+}
+
+/*
+ * GSM 08.08 § 3.1.9.1 and 3.2.1.21...
+ * release our gsm_subscriber_connection and send message
+ */
+static int bssmap_handle_clear_command(struct osmo_bsc_sccp_con *conn,
+				       struct msgb *msg, unsigned int payload_length)
+{
+	struct msgb *resp;
+
+	/* TODO: handle the cause of this package */
+
+	if (conn->conn) {
+		LOGP(DMSC, LOGL_DEBUG, "Releasing all transactions on %p\n", conn);
+		gsm0808_clear(conn->conn);
+		subscr_con_free(conn->conn);
+		conn->conn = NULL;
+	}
+
+	/* send the clear complete message */
+	resp = gsm0808_create_clear_complete();
+	if (!resp) {
+		LOGP(DMSC, LOGL_ERROR, "Sending clear complete failed.\n");
+		return -1;
+	}
+
+	bsc_queue_for_msc(conn, resp);
+	return 0;
+}
+
+/*
+ * GSM 08.08 § 3.4.7 cipher mode handling. We will have to pick
+ * the cipher to be used for this. In case we are already using
+ * a cipher we will have to send cipher mode reject to the MSC,
+ * otherwise we will have to pick something that we and the MS
+ * is supporting. Currently we are doing it in a rather static
+ * way by picking one ecnryption or no encrytpion.
+ */
+static int bssmap_handle_cipher_mode(struct osmo_bsc_sccp_con *conn,
+				     struct msgb *msg, unsigned int payload_length)
+{
+	uint16_t len;
+	struct gsm_network *network = NULL;
+	const uint8_t *data;
+	struct tlv_parsed tp;
+	struct msgb *resp;
+	int reject_cause = -1;
+	int include_imeisv = 1;
+
+	if (!conn->conn) {
+		LOGP(DMSC, LOGL_ERROR, "No lchan/msc_data in cipher mode command.\n");
+		goto reject;
+	}
+
+	if (conn->ciphering_handled) {
+		LOGP(DMSC, LOGL_ERROR, "Already seen ciphering command. Protocol Error.\n");
+		goto reject;
+	}
+
+	conn->ciphering_handled = 1;
+
+	tlv_parse(&tp, gsm0808_att_tlvdef(), msg->l4h + 1, payload_length - 1, 0, 0);
+	if (!TLVP_PRESENT(&tp, GSM0808_IE_ENCRYPTION_INFORMATION)) {
+		LOGP(DMSC, LOGL_ERROR, "IE Encryption Information missing.\n");
+		goto reject;
+	}
+
+	/*
+	 * check if our global setting is allowed
+	 *  - Currently we check for A5/0 and A5/1
+	 *  - Copy the key if that is necessary
+	 *  - Otherwise reject
+	 */
+	len = TLVP_LEN(&tp, GSM0808_IE_ENCRYPTION_INFORMATION);
+	if (len < 1) {
+		LOGP(DMSC, LOGL_ERROR, "IE Encryption Information is too short.\n");
+		goto reject;
+	}
+
+	network = conn->conn->bts->network;
+	data = TLVP_VAL(&tp, GSM0808_IE_ENCRYPTION_INFORMATION);
+
+	if (TLVP_PRESENT(&tp, GSM0808_IE_CIPHER_RESPONSE_MODE))
+		include_imeisv = TLVP_VAL(&tp, GSM0808_IE_CIPHER_RESPONSE_MODE)[0] & 0x1;
+
+	if (network->a5_encryption == 0 && (data[0] & 0x1) == 0x1) {
+		gsm0808_cipher_mode(conn->conn, 0, NULL, 0, include_imeisv);
+	} else if (network->a5_encryption != 0 && (data[0] & 0x2) == 0x2) {
+		gsm0808_cipher_mode(conn->conn, 1, &data[1], len - 1, include_imeisv);
+	} else {
+		LOGP(DMSC, LOGL_ERROR, "Can not select encryption...\n");
+		goto reject;
+	}
+
+reject:
+	resp = gsm0808_create_cipher_reject(reject_cause);
+	if (!resp) {
+		LOGP(DMSC, LOGL_ERROR, "Sending the cipher reject failed.\n");
+		return -1;
+	}
+
+	bsc_queue_for_msc(conn, resp);
+	return -1;
+}
+
+/*
+ * Handle the assignment request message.
+ *
+ * See §3.2.1.1 for the message type
+ */
+static int bssmap_handle_assignm_req(struct osmo_bsc_sccp_con *conn,
+				     struct msgb *msg, unsigned int length)
+{
+	struct msgb *resp;
+	struct gsm_network *network;
+	struct tlv_parsed tp;
+	uint8_t *data;
+	uint16_t cic;
+	uint8_t timeslot;
+	uint8_t multiplex;
+	enum gsm48_chan_mode chan_mode = GSM48_CMODE_SIGN;
+	int i, supported, port, full_rate = -1;
+
+	if (!conn->conn) {
+		LOGP(DMSC, LOGL_ERROR, "No lchan/msc_data in cipher mode command.\n");
+		return -1;
+	}
+
+	network = conn->conn->bts->network;
+	tlv_parse(&tp, gsm0808_att_tlvdef(), msg->l4h + 1, length - 1, 0, 0);
+
+	if (!TLVP_PRESENT(&tp, GSM0808_IE_CHANNEL_TYPE)) {
+		LOGP(DMSC, LOGL_ERROR, "Mandantory channel type not present.\n");
+		goto reject;
+	}
+
+	if (!TLVP_PRESENT(&tp, GSM0808_IE_CIRCUIT_IDENTITY_CODE)) {
+		LOGP(DMSC, LOGL_ERROR, "Identity code missing. Audio routing will not work.\n");
+		goto reject;
+	}
+
+	cic = ntohs(read_data16(TLVP_VAL(&tp, GSM0808_IE_CIRCUIT_IDENTITY_CODE)));
+	timeslot = cic & 0x1f;
+	multiplex = (cic & ~0x1f) >> 5;
+
+	/*
+	 * Currently we only support a limited subset of all
+	 * possible channel types. The limitation ends by not using
+	 * multi-slot, limiting the channel coding, speech...
+	 */
+	if (TLVP_LEN(&tp, GSM0808_IE_CHANNEL_TYPE) < 3) {
+		LOGP(DMSC, LOGL_ERROR, "ChannelType len !=3 not supported: %d\n",
+			TLVP_LEN(&tp, GSM0808_IE_CHANNEL_TYPE));
+		goto reject;
+	}
+
+	/*
+	 * Try to figure out if we support the proposed speech codecs. For
+	 * now we will always pick the full rate codecs.
+	 */
+
+	data = (uint8_t *) TLVP_VAL(&tp, GSM0808_IE_CHANNEL_TYPE);
+	if ((data[0] & 0xf) != 0x1) {
+		LOGP(DMSC, LOGL_ERROR, "ChannelType != speech: %d\n", data[0]);
+		goto reject;
+	}
+
+	if (data[1] != GSM0808_SPEECH_FULL_PREF && data[1] != GSM0808_SPEECH_HALF_PREF) {
+		LOGP(DMSC, LOGL_ERROR, "ChannelType full not allowed: %d\n", data[1]);
+		goto reject;
+	}
+
+	/*
+	 * go through the list of preferred codecs of our gsm network
+	 * and try to find it among the permitted codecs. If we found
+	 * it we will send chan_mode to the right mode and break the
+	 * inner loop. The outer loop will exit due chan_mode having
+	 * the correct value.
+	 */
+	full_rate = 0;
+	for (supported = 0;
+		chan_mode == GSM48_CMODE_SIGN && supported < network->msc_data->audio_length;
+		++supported) {
+
+		int perm_val = audio_support_to_gsm88(network->msc_data->audio_support[supported]);
+		for (i = 2; i < TLVP_LEN(&tp, GSM0808_IE_CHANNEL_TYPE); ++i) {
+			if ((data[i] & 0x7f) == perm_val) {
+				chan_mode = gsm88_to_chan_mode(perm_val);
+				full_rate = (data[i] & 0x4) == 0;
+				break;
+			} else if ((data[i] & 0x80) == 0x00) {
+				break;
+			}
+		}
+	}
+
+	if (chan_mode == GSM48_CMODE_SIGN) {
+		LOGP(DMSC, LOGL_ERROR, "No supported audio type found.\n");
+		goto reject;
+	}
+
+	/* map it to a MGCP Endpoint and a RTP port */
+	port = mgcp_timeslot_to_endpoint(multiplex, timeslot);
+	conn->rtp_port = rtp_calculate_port(port,
+						network->msc_data->rtp_base);
+
+	return gsm0808_assign_req(conn->conn, chan_mode, full_rate);
+
+reject:
+	resp = gsm0808_create_assignment_failure(GSM0808_CAUSE_NO_RADIO_RESOURCE_AVAILABLE, NULL);
+	if (!resp) {
+		LOGP(DMSC, LOGL_ERROR, "Channel allocation failure.\n");
+		return -1;
+	}
+
+	bsc_queue_for_msc(conn, resp);
+	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)
+{
+	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_CLEAR_CMD:
+		ret = bssmap_handle_clear_command(conn, msg, length);
+		break;
+	case BSS_MAP_MSG_CIPHER_MODE_CMD:
+		ret = bssmap_handle_cipher_mode(conn, msg, length);
+		break;
+	case BSS_MAP_MSG_ASSIGMENT_RQST:
+		ret = bssmap_handle_assignm_req(conn, msg, length);
+		break;
+	default:
+		LOGP(DMSC, LOGL_DEBUG, "Unimplemented msg type: %d\n", msg->l4h[0]);
+		break;
+	}
+
+	return ret;
+}
+
+static int dtap_rcvmsg(struct osmo_bsc_sccp_con *conn,
+		       struct msgb *msg, unsigned int length)
+{
+	struct dtap_header *header;
+	struct msgb *gsm48;
+	uint8_t *data;
+
+	if (!conn->conn) {
+		LOGP(DMSC, LOGL_ERROR, "No subscriber connection available\n");
+		return -1;
+	}
+
+	header = (struct dtap_header *) msg->l3h;
+	if (sizeof(*header) >= length) {
+		LOGP(DMSC, LOGL_ERROR, "The DTAP header does not fit. Wanted: %u got: %u\n", sizeof(*header), length);
+                LOGP(DMSC, LOGL_ERROR, "hex: %s\n", hexdump(msg->l3h, length));
+                return -1;
+	}
+
+	if (header->length > length - sizeof(*header)) {
+		LOGP(DMSC, LOGL_ERROR, "The DTAP l4 information does not fit: header: %u length: %u\n", header->length, length);
+                LOGP(DMSC, LOGL_ERROR, "hex: %s\n", hexdump(msg->l3h, length));
+		return -1;
+	}
+
+	LOGP(DMSC, LOGL_DEBUG, "DTAP message: SAPI: %u CHAN: %u\n", header->link_id & 0x07, header->link_id & 0xC0);
+
+	/* forward the data */
+	gsm48 = gsm48_msgb_alloc();
+	if (!gsm48) {
+		LOGP(DMSC, LOGL_ERROR, "Allocation of the message failed.\n");
+		return -1;
+	}
+
+	gsm48->l3h = gsm48->data;
+	data = msgb_put(gsm48, length - sizeof(*header));
+	memcpy(data, msg->l3h + sizeof(*header), length - sizeof(*header));
+
+	/* pass it to the filter for extra actions */
+	bsc_scan_msc_msg(conn->conn, gsm48);
+	return gsm0808_submit_dtap(conn->conn, gsm48, header->link_id, 1);
+}
+
+int bsc_handle_udt(struct gsm_network *network,
+		   struct bsc_msc_connection *conn,
+		   struct msgb *msgb, unsigned int length)
+{
+	struct bssmap_header *bs;
+
+	LOGP(DMSC, LOGL_DEBUG, "Incoming SCCP message ftom MSC: %s\n",
+		hexdump(msgb->l3h, length));
+
+	if (length < sizeof(*bs)) {
+		LOGP(DMSC, LOGL_ERROR, "The header is too short.\n");
+		return -1;
+	}
+
+	bs = (struct bssmap_header *) msgb->l3h;
+	if (bs->length < length - sizeof(*bs))
+		return -1;
+
+	switch (bs->type) {
+	case BSSAP_MSG_BSS_MANAGEMENT:
+		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);
+	}
+
+	return 0;
+}
+
+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;
+}