| /* 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 <osmocom/gsm/protocol/gsm_08_08.h> |
| #include <osmocom/gsm/gsm0808.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", osmo_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", osmo_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", osmo_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", |
| osmo_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; |
| } |