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Diffstat (limited to 'src/osmo-bsc/osmo_bsc_bssap.c')
-rw-r--r--src/osmo-bsc/osmo_bsc_bssap.c548
1 files changed, 548 insertions, 0 deletions
diff --git a/src/osmo-bsc/osmo_bsc_bssap.c b/src/osmo-bsc/osmo_bsc_bssap.c
new file mode 100644
index 00000000..f8711314
--- /dev/null
+++ b/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;
+}