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-rw-r--r--src/libbsc/bsc_api.c675
1 files changed, 675 insertions, 0 deletions
diff --git a/src/libbsc/bsc_api.c b/src/libbsc/bsc_api.c
new file mode 100644
index 00000000..0f09aecd
--- /dev/null
+++ b/src/libbsc/bsc_api.c
@@ -0,0 +1,675 @@
+/* GSM 08.08 like API for OpenBSC. The bridge from MSC to BSC */
+
+/* (C) 2010 by Holger Hans Peter Freyther
+ * (C) 2010 by On-Waves
+ * (C) 2009 by Harald Welte <laforge@gnumonks.org>
+ *
+ * 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/bsc_api.h>
+#include <openbsc/bsc_rll.h>
+#include <openbsc/gsm_data.h>
+#include <openbsc/gsm_subscriber.h>
+#include <openbsc/signal.h>
+#include <openbsc/abis_rsl.h>
+#include <openbsc/chan_alloc.h>
+#include <openbsc/handover.h>
+#include <openbsc/debug.h>
+#include <openbsc/gsm_04_08.h>
+
+#include <osmocore/protocol/gsm_08_08.h>
+
+#include <osmocore/talloc.h>
+
+#define GSM0808_T10_VALUE 6, 0
+
+static LLIST_HEAD(sub_connections);
+
+static void rll_ind_cb(struct gsm_lchan *, uint8_t, void *, enum bsc_rllr_ind);
+static void send_sapi_reject(struct gsm_subscriber_connection *conn, int link_id);
+static void handle_release(struct gsm_subscriber_connection *conn, struct bsc_api *bsc, struct gsm_lchan *lchan);
+static void handle_chan_ack(struct gsm_subscriber_connection *conn, struct bsc_api *bsc, struct gsm_lchan *lchan);
+static void handle_chan_nack(struct gsm_subscriber_connection *conn, struct bsc_api *bsc, struct gsm_lchan *lchan);
+
+/* GSM 08.08 3.2.2.33 */
+static u_int8_t lchan_to_chosen_channel(struct gsm_lchan *lchan)
+{
+ u_int8_t channel_mode = 0, channel = 0;
+
+ switch (lchan->tch_mode) {
+ case GSM48_CMODE_SPEECH_V1:
+ case GSM48_CMODE_SPEECH_EFR:
+ case GSM48_CMODE_SPEECH_AMR:
+ channel_mode = 0x9;
+ break;
+ case GSM48_CMODE_SIGN:
+ channel_mode = 0x8;
+ break;
+ case GSM48_CMODE_DATA_14k5:
+ channel_mode = 0xe;
+ break;
+ case GSM48_CMODE_DATA_12k0:
+ channel_mode = 0xb;
+ break;
+ case GSM48_CMODE_DATA_6k0:
+ channel_mode = 0xc;
+ break;
+ case GSM48_CMODE_DATA_3k6:
+ channel_mode = 0xd;
+ break;
+ }
+
+ switch (lchan->type) {
+ case GSM_LCHAN_NONE:
+ channel = 0x0;
+ break;
+ case GSM_LCHAN_SDCCH:
+ channel = 0x1;
+ break;
+ case GSM_LCHAN_TCH_F:
+ channel = 0x8;
+ break;
+ case GSM_LCHAN_TCH_H:
+ channel = 0x9;
+ break;
+ case GSM_LCHAN_UNKNOWN:
+ LOGP(DMSC, LOGL_ERROR, "Unknown lchan type: %p\n", lchan);
+ break;
+ }
+
+ return channel_mode << 4 | channel;
+}
+
+static u_int8_t chan_mode_to_speech(struct gsm_lchan *lchan)
+{
+ int mode = 0;
+
+ switch (lchan->tch_mode) {
+ case GSM48_CMODE_SPEECH_V1:
+ mode = 1;
+ break;
+ case GSM48_CMODE_SPEECH_EFR:
+ mode = 0x11;
+ break;
+ case GSM48_CMODE_SPEECH_AMR:
+ mode = 0x21;
+ break;
+ case GSM48_CMODE_SIGN:
+ case GSM48_CMODE_DATA_14k5:
+ case GSM48_CMODE_DATA_12k0:
+ case GSM48_CMODE_DATA_6k0:
+ case GSM48_CMODE_DATA_3k6:
+ default:
+ LOGP(DMSC, LOGL_ERROR, "Using non speech mode: %d\n", mode);
+ return 0;
+ break;
+ }
+
+ /* assume to always do AMR HR on any TCH type */
+ if (lchan->type == GSM_LCHAN_TCH_H ||
+ lchan->tch_mode == GSM48_CMODE_SPEECH_AMR)
+ mode |= 0x4;
+
+ return mode;
+}
+
+static void assignment_t10_timeout(void *_conn)
+{
+ struct bsc_api *api;
+ struct gsm_subscriber_connection *conn =
+ (struct gsm_subscriber_connection *) _conn;
+
+ LOGP(DMSC, LOGL_ERROR, "Assigment T10 timeout on %p\n", conn);
+
+ /* normal release on the secondary channel */
+ lchan_release(conn->secondary_lchan, 0, 1);
+ conn->secondary_lchan = NULL;
+
+ /* inform them about the failure */
+ api = conn->bts->network->bsc_api;
+ api->assign_fail(conn, GSM0808_CAUSE_NO_RADIO_RESOURCE_AVAILABLE, NULL);
+}
+
+/*
+ * Start a new assignment and make sure that it is completed within T10 either
+ * positively, negatively or by the timeout.
+ *
+ * 1.) allocate a new lchan
+ * 2.) copy the encryption key and other data from the
+ * old to the new channel.
+ * 3.) RSL Channel Activate this channel and wait
+ *
+ * -> Signal handler for the LCHAN
+ * 4.) Send GSM 04.08 assignment command to the MS
+ *
+ * -> Assignment Complete/Assignment Failure
+ * 5.) Release the SDCCH, continue signalling on the new link
+ */
+static int handle_new_assignment(struct gsm_subscriber_connection *conn, int chan_mode, int full_rate)
+{
+ struct gsm_lchan *new_lchan;
+ int chan_type;
+
+ chan_type = full_rate ? GSM_LCHAN_TCH_F : GSM_LCHAN_TCH_H;
+
+ new_lchan = lchan_alloc(conn->bts, chan_type, 0);
+
+ if (!new_lchan) {
+ LOGP(DMSC, LOGL_NOTICE, "No free channel.\n");
+ return -1;
+ }
+
+ /* copy old data to the new channel */
+ memcpy(&new_lchan->encr, &conn->lchan->encr, sizeof(new_lchan->encr));
+ new_lchan->ms_power = conn->lchan->ms_power;
+ new_lchan->bs_power = conn->lchan->bs_power;
+
+ /* copy new data to it */
+ new_lchan->tch_mode = chan_mode;
+ new_lchan->rsl_cmode = RSL_CMOD_SPD_SPEECH;
+
+ /* handle AMR correctly */
+ if (chan_mode == GSM48_CMODE_SPEECH_AMR) {
+ new_lchan->mr_conf.ver = 1;
+ new_lchan->mr_conf.icmi = 1;
+ new_lchan->mr_conf.m5_90 = 1;
+ }
+
+ if (rsl_chan_activate_lchan(new_lchan, 0x1, 0, 0) < 0) {
+ LOGP(DHO, LOGL_ERROR, "could not activate channel\n");
+ lchan_free(new_lchan);
+ return -1;
+ }
+
+ /* remember that we have the channel */
+ conn->secondary_lchan = new_lchan;
+ new_lchan->conn = conn;
+
+ rsl_lchan_set_state(new_lchan, LCHAN_S_ACT_REQ);
+ return 0;
+}
+
+struct gsm_subscriber_connection *subscr_con_allocate(struct gsm_lchan *lchan)
+{
+ struct gsm_subscriber_connection *conn;
+
+ conn = talloc_zero(lchan->ts->trx->bts->network, struct gsm_subscriber_connection);
+ if (!conn)
+ return NULL;
+
+ /* Configure the time and start it so it will be closed */
+ conn->lchan = lchan;
+ conn->bts = lchan->ts->trx->bts;
+ lchan->conn = conn;
+ llist_add_tail(&conn->entry, &sub_connections);
+ return conn;
+}
+
+/* TODO: move subscriber put here... */
+void subscr_con_free(struct gsm_subscriber_connection *conn)
+{
+ if (!conn)
+ return;
+
+
+ if (conn->subscr) {
+ subscr_put(conn->subscr);
+ conn->subscr = NULL;
+ }
+
+
+ if (conn->ho_lchan) {
+ LOGP(DNM, LOGL_ERROR, "The ho_lchan should have been cleared.\n");
+ conn->ho_lchan->conn = NULL;
+ }
+
+ if (conn->lchan) {
+ LOGP(DNM, LOGL_ERROR, "The lchan should have been cleared.\n");
+ conn->lchan->conn = NULL;
+ }
+
+ if (conn->secondary_lchan) {
+ LOGP(DNM, LOGL_ERROR, "The secondary_lchan should have been cleared.\n");
+ conn->secondary_lchan->conn = NULL;
+ }
+
+ llist_del(&conn->entry);
+ talloc_free(conn);
+}
+
+int bsc_api_init(struct gsm_network *network, struct bsc_api *api)
+{
+ network->bsc_api = api;
+ return 0;
+}
+
+int gsm0808_submit_dtap(struct gsm_subscriber_connection *conn,
+ struct msgb *msg, int link_id, int allow_sach)
+{
+ uint8_t sapi;
+
+
+ if (!conn->lchan) {
+ LOGP(DMSC, LOGL_ERROR,
+ "Called submit dtap without an lchan.\n");
+ msgb_free(msg);
+ return -1;
+ }
+
+ sapi = link_id & 0x7;
+ msg->lchan = conn->lchan;
+ msg->trx = msg->lchan->ts->trx;
+
+ /* If we are on a TCH and need to submit a SMS (on SAPI=3) we need to use the SACH */
+ if (allow_sach && sapi != 0) {
+ if (conn->lchan->type == GSM_LCHAN_TCH_F || conn->lchan->type == GSM_LCHAN_TCH_H)
+ link_id |= 0x40;
+ }
+
+ msg->l3h = msg->data;
+ if (conn->lchan->sapis[sapi] == LCHAN_SAPI_UNUSED) {
+ OBSC_LINKID_CB(msg) = link_id;
+ if (rll_establish(msg->lchan, sapi, rll_ind_cb, msg) != 0) {
+ msgb_free(msg);
+ send_sapi_reject(conn, link_id);
+ return -1;
+ }
+ return 0;
+ } else {
+ return rsl_data_request(msg, link_id);
+ }
+}
+
+/**
+ * Send a GSM08.08 Assignment Request. Right now this does not contain the
+ * audio codec type or the allowed rates for the config. It is assumed that
+ * this is for audio handling and that when we have a TCH it is capable of
+ * handling the audio codec. On top of that it is assumed that we are using
+ * AMR 5.9 when assigning a TCH/H.
+ */
+int gsm0808_assign_req(struct gsm_subscriber_connection *conn, int chan_mode, int full_rate)
+{
+ struct bsc_api *api;
+ api = conn->bts->network->bsc_api;
+
+ if (conn->lchan->type == GSM_LCHAN_SDCCH) {
+ if (handle_new_assignment(conn, chan_mode, full_rate) != 0)
+ goto error;
+ } else {
+ LOGP(DMSC, LOGL_NOTICE,
+ "Sending ChanModify for speech %d %d\n", chan_mode, full_rate);
+ if (chan_mode == GSM48_CMODE_SPEECH_AMR) {
+ conn->lchan->mr_conf.ver = 1;
+ conn->lchan->mr_conf.icmi = 1;
+ conn->lchan->mr_conf.m5_90 = 1;
+ }
+
+ gsm48_lchan_modify(conn->lchan, chan_mode);
+ }
+
+ /* we will now start the timer to complete the assignment */
+ conn->T10.cb = assignment_t10_timeout;
+ conn->T10.data = conn;
+ bsc_schedule_timer(&conn->T10, GSM0808_T10_VALUE);
+ return 0;
+
+error:
+ api->assign_fail(conn, 0, NULL);
+ return -1;
+}
+
+int gsm0808_page(struct gsm_bts *bts, unsigned int page_group, unsigned int mi_len,
+ uint8_t *mi, int chan_type)
+{
+ return rsl_paging_cmd(bts, page_group, mi_len, mi, chan_type);
+}
+
+static void handle_ass_compl(struct gsm_subscriber_connection *conn,
+ struct msgb *msg)
+{
+ struct gsm48_hdr *gh;
+ struct bsc_api *api = conn->bts->network->bsc_api;
+
+ if (conn->secondary_lchan != msg->lchan) {
+ LOGP(DMSC, LOGL_ERROR, "Assignment Compl should occur on second lchan.\n");
+ return;
+ }
+
+ gh = msgb_l3(msg);
+ if (msgb_l3len(msg) - sizeof(*gh) != 1) {
+ LOGP(DMSC, LOGL_ERROR, "Assignment Compl invalid: %lu\n",
+ msgb_l3len(msg) - sizeof(*gh));
+ return;
+ }
+
+ /* swap channels */
+ bsc_del_timer(&conn->T10);
+
+ lchan_release(conn->lchan, 0, 1);
+ conn->lchan = conn->secondary_lchan;
+ conn->secondary_lchan = NULL;
+
+ if (is_ipaccess_bts(conn->bts) && conn->lchan->tch_mode != GSM48_CMODE_SIGN)
+ rsl_ipacc_crcx(conn->lchan);
+
+ api->assign_compl(conn, gh->data[0],
+ lchan_to_chosen_channel(conn->lchan),
+ conn->lchan->encr.alg_id,
+ chan_mode_to_speech(conn->lchan));
+}
+
+static void handle_ass_fail(struct gsm_subscriber_connection *conn,
+ struct msgb *msg)
+{
+ struct bsc_api *api = conn->bts->network->bsc_api;
+ uint8_t *rr_failure;
+ struct gsm48_hdr *gh;
+
+
+ if (conn->lchan != msg->lchan) {
+ LOGP(DMSC, LOGL_ERROR, "Assignment failure should occur on primary lchan.\n");
+ return;
+ }
+
+ /* stop the timer and release it */
+ bsc_del_timer(&conn->T10);
+ lchan_release(conn->secondary_lchan, 0, 1);
+ conn->secondary_lchan = NULL;
+
+ gh = msgb_l3(msg);
+ if (msgb_l3len(msg) - sizeof(*gh) != 1) {
+ LOGP(DMSC, LOGL_ERROR, "assignemnt failure unhandled: %lu\n",
+ msgb_l3len(msg) - sizeof(*gh));
+ rr_failure = NULL;
+ } else {
+ rr_failure = &gh->data[0];
+ }
+
+ api->assign_fail(conn,
+ GSM0808_CAUSE_RADIO_INTERFACE_MESSAGE_FAILURE,
+ rr_failure);
+}
+
+static void dispatch_dtap(struct gsm_subscriber_connection *conn,
+ uint8_t link_id, struct msgb *msg)
+{
+ struct bsc_api *api = msg->lchan->ts->trx->bts->network->bsc_api;
+ struct gsm48_hdr *gh;
+ uint8_t pdisc;
+ int rc;
+
+ if (msgb_l3len(msg) < sizeof(*gh)) {
+ LOGP(DMSC, LOGL_ERROR, "Message too short for a GSM48 header.\n");
+ return;
+ }
+
+ gh = msgb_l3(msg);
+ pdisc = gh->proto_discr & 0x0f;
+ switch (pdisc) {
+ case GSM48_PDISC_RR:
+ switch (gh->msg_type) {
+ case GSM48_MT_RR_CIPH_M_COMPL:
+ if (api->cipher_mode_compl)
+ return api->cipher_mode_compl(conn, msg,
+ conn->lchan->encr.alg_id);
+ break;
+ case GSM48_MT_RR_ASS_COMPL:
+ handle_ass_compl(conn, msg);
+ break;
+ case GSM48_MT_RR_ASS_FAIL:
+ handle_ass_fail(conn, msg);
+ break;
+ case GSM48_MT_RR_CHAN_MODE_MODIF_ACK:
+ bsc_del_timer(&conn->T10);
+ rc = gsm48_rx_rr_modif_ack(msg);
+ if (rc < 0 && api->assign_fail) {
+ api->assign_fail(conn,
+ GSM0808_CAUSE_NO_RADIO_RESOURCE_AVAILABLE,
+ NULL);
+ } else if (rc >= 0 && api->assign_compl)
+ api->assign_compl(conn, 0,
+ lchan_to_chosen_channel(conn->lchan),
+ conn->lchan->encr.alg_id,
+ chan_mode_to_speech(conn->lchan));
+ return;
+ break;
+ }
+ break;
+ case GSM48_PDISC_MM:
+ break;
+ }
+
+ /* default case */
+ if (api->dtap)
+ api->dtap(conn, link_id, msg);
+}
+
+int gsm0408_rcvmsg(struct msgb *msg, uint8_t link_id)
+{
+ int rc;
+ struct bsc_api *api = msg->lchan->ts->trx->bts->network->bsc_api;
+ struct gsm_lchan *lchan;
+
+ lchan = msg->lchan;
+ if (lchan->state != LCHAN_S_ACTIVE) {
+ LOGP(DRSL, LOGL_INFO, "Got data in non active state(%s), "
+ "discarding.\n", gsm_lchans_name(lchan->state));
+ return -1;
+ }
+
+
+ if (lchan->conn) {
+ dispatch_dtap(lchan->conn, link_id, msg);
+ } else {
+ rc = BSC_API_CONN_POL_REJECT;
+ lchan->conn = subscr_con_allocate(msg->lchan);
+ if (!lchan->conn) {
+ lchan_release(lchan, 0, 0);
+ return -1;
+ }
+
+ rc = api->compl_l3(lchan->conn, msg, 0);
+
+ if (rc != BSC_API_CONN_POL_ACCEPT) {
+ lchan->conn->lchan = NULL;
+ subscr_con_free(lchan->conn);
+ lchan_release(lchan, 0, 0);
+ }
+ }
+
+ return 0;
+}
+
+int gsm0808_cipher_mode(struct gsm_subscriber_connection *conn, int cipher,
+ const uint8_t *key, int len, int include_imeisv)
+{
+ if (cipher > 0 && key == NULL) {
+ LOGP(DRSL, LOGL_ERROR, "Need to have an encrytpion key.\n");
+ return -1;
+ }
+
+ if (len > MAX_A5_KEY_LEN) {
+ LOGP(DRSL, LOGL_ERROR, "The key is too long: %d\n", len);
+ return -1;
+ }
+
+ conn->lchan->encr.alg_id = RSL_ENC_ALG_A5(cipher);
+ if (key) {
+ conn->lchan->encr.key_len = len;
+ memcpy(conn->lchan->encr.key, key, len);
+ }
+
+ return gsm48_send_rr_ciph_mode(conn->lchan, include_imeisv);
+}
+
+/*
+ * Release all occupied RF Channels but stay around for more.
+ */
+int gsm0808_clear(struct gsm_subscriber_connection *conn)
+{
+ if (conn->ho_lchan)
+ bsc_clear_handover(conn, 1);
+
+ if (conn->secondary_lchan)
+ lchan_release(conn->secondary_lchan, 0, 1);
+
+ if (conn->lchan)
+ lchan_release(conn->lchan, 1, 0);
+
+ conn->lchan = NULL;
+ conn->secondary_lchan = NULL;
+ conn->ho_lchan = NULL;
+ conn->bts = NULL;
+
+ bsc_del_timer(&conn->T10);
+
+ return 0;
+}
+
+static void send_sapi_reject(struct gsm_subscriber_connection *conn, int link_id)
+{
+ struct bsc_api *api;
+
+ if (!conn)
+ return;
+
+ api = conn->bts->network->bsc_api;
+ if (!api || !api->sapi_n_reject)
+ return;
+
+ api->sapi_n_reject(conn, link_id);
+}
+
+static void rll_ind_cb(struct gsm_lchan *lchan, uint8_t link_id, void *_data, enum bsc_rllr_ind rllr_ind)
+{
+ struct msgb *msg = _data;
+
+ /*
+ * There seems to be a small window that the RLL timer can
+ * fire after a lchan_release call and before the S_CHALLOC_FREED
+ * is called. Check if a conn is set before proceeding.
+ */
+ if (!lchan->conn)
+ return;
+
+ switch (rllr_ind) {
+ case BSC_RLLR_IND_EST_CONF:
+ rsl_data_request(msg, OBSC_LINKID_CB(msg));
+ break;
+ case BSC_RLLR_IND_REL_IND:
+ case BSC_RLLR_IND_ERR_IND:
+ case BSC_RLLR_IND_TIMEOUT:
+ send_sapi_reject(lchan->conn, OBSC_LINKID_CB(msg));
+ msgb_free(msg);
+ break;
+ }
+}
+
+static int bsc_handle_lchan_signal(unsigned int subsys, unsigned int signal,
+ void *handler_data, void *signal_data)
+{
+ struct bsc_api *bsc;
+ struct gsm_lchan *lchan;
+ struct lchan_signal_data *lchan_data;
+
+ if (subsys != SS_LCHAN)
+ return 0;
+
+
+ lchan_data = signal_data;
+ if (!lchan_data->lchan || !lchan_data->lchan->conn)
+ return 0;
+
+ lchan = lchan_data->lchan;
+ bsc = lchan->ts->trx->bts->network->bsc_api;
+ if (!bsc)
+ return 0;
+
+ switch (signal) {
+ case S_LCHAN_UNEXPECTED_RELEASE:
+ handle_release(lchan->conn, bsc, lchan);
+ break;
+ case S_LCHAN_ACTIVATE_ACK:
+ handle_chan_ack(lchan->conn, bsc, lchan);
+ break;
+ case S_LCHAN_ACTIVATE_NACK:
+ handle_chan_nack(lchan->conn, bsc, lchan);
+ break;
+ }
+
+ return 0;
+}
+
+static void handle_release(struct gsm_subscriber_connection *conn,
+ struct bsc_api *bsc, struct gsm_lchan *lchan)
+{
+ int destruct = 1;
+
+ if (conn->secondary_lchan == lchan) {
+ bsc_del_timer(&conn->T10);
+ conn->secondary_lchan = NULL;
+
+ bsc->assign_fail(conn,
+ GSM0808_CAUSE_RADIO_INTERFACE_FAILURE,
+ NULL);
+ }
+
+ /* clear the connection now */
+ if (bsc->clear_request)
+ destruct = bsc->clear_request(conn, 0);
+
+ /* now give up all channels */
+ if (conn->lchan == lchan)
+ conn->lchan = NULL;
+ if (conn->ho_lchan == lchan) {
+ bsc_clear_handover(conn, 0);
+ conn->ho_lchan = NULL;
+ }
+ lchan->conn = NULL;
+
+ gsm0808_clear(conn);
+
+ if (destruct)
+ subscr_con_free(conn);
+}
+
+static void handle_chan_ack(struct gsm_subscriber_connection *conn,
+ struct bsc_api *api, struct gsm_lchan *lchan)
+{
+ if (conn->secondary_lchan != lchan)
+ return;
+
+ LOGP(DMSC, LOGL_NOTICE, "Sending assignment on chan: %p\n", lchan);
+ gsm48_send_rr_ass_cmd(conn->lchan, lchan, 0x3);
+}
+
+static void handle_chan_nack(struct gsm_subscriber_connection *conn,
+ struct bsc_api *api, struct gsm_lchan *lchan)
+{
+ if (conn->secondary_lchan != lchan)
+ return;
+
+ LOGP(DMSC, LOGL_ERROR, "Channel activation failed. Waiting for timeout now\n");
+ conn->secondary_lchan->conn = NULL;
+ conn->secondary_lchan = NULL;
+}
+
+static __attribute__((constructor)) void on_dso_load_bsc(void)
+{
+ register_signal_handler(SS_LCHAN, bsc_handle_lchan_signal, NULL);
+}