/* GSM 08.08 BSSMAP handling */ /* (C) 2009-2012 by Holger Hans Peter Freyther * (C) 2009-2012 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 . * */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define IP_V4_ADDR_LEN 4 /* * helpers for the assignment command */ /* Helper function for match_codec_pref(), looks up a matching permitted speech * value for a given msc audio codec pref */ 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; } } } /* Helper function for match_codec_pref(), looks up a matching chan mode for * a given permitted speech value */ 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; default: LOGP(DMSC, LOGL_FATAL, "Unsupported permitted speech selected, assuming AMR as channel mode...\n"); return GSM48_CMODE_SPEECH_AMR; } } /* Helper function for match_codec_pref(), tests if a given audio support * matches one of the permitted speech settings of the channel type element. * The matched permitted speech value is then also compared against the * speech codec list. (optional, only relevant for AoIP) */ static bool test_codec_pref(const struct gsm0808_channel_type *ct, const struct gsm0808_speech_codec_list *scl, uint8_t perm_spch) { unsigned int i; bool match = false; struct gsm0808_speech_codec sc; int rc; /* Try to finde the given permitted speech value in the * codec list of the channel type element */ for (i = 0; i < ct->perm_spch_len; i++) { if (ct->perm_spch[i] == perm_spch) { match = true; break; } } /* If we do not have a speech codec list to test against, * we just exit early (will be always the case in non-AoIP networks) */ if (!scl) return match; /* If we failed to match until here, there is no * point in testing further */ if (match == false) return false; /* Extrapolate speech codec data */ rc = gsm0808_speech_codec_from_chan_type(&sc, perm_spch); if (rc < 0) return false; /* Try to find extrapolated speech codec data in * the speech codec list */ for (i = 0; i < scl->len; i++) { if (memcmp(&sc, &scl->codec[i], sizeof(sc)) == 0) return true; } return false; } /* Helper function for bssmap_handle_assignm_req(), matches the codec * preferences from the MSC with the codec preferences */ static int match_codec_pref(int *full_rate, enum gsm48_chan_mode *chan_mode, const struct gsm0808_channel_type *ct, const struct gsm0808_speech_codec_list *scl, const struct bsc_msc_data *msc) { unsigned int i; uint8_t perm_spch; bool match = false; for (i = 0; i < msc->audio_length; i++) { perm_spch = audio_support_to_gsm88(msc->audio_support[i]); if (test_codec_pref(ct, scl, perm_spch)) { match = true; break; } } /* Exit without result, in case no match can be deteched */ if (!match) { *full_rate = -1; *chan_mode = GSM48_CMODE_SIGN; return -1; } /* Check if the result is a half or full rate codec */ if (perm_spch == GSM0808_PERM_HR1 || perm_spch == GSM0808_PERM_HR2 || perm_spch == GSM0808_PERM_HR3 || perm_spch == GSM0808_PERM_HR4 || perm_spch == GSM0808_PERM_HR6) *full_rate = 0; else *full_rate = 1; /* Lookup a channel mode for the selected codec */ *chan_mode = gsm88_to_chan_mode(perm_spch); return 0; } static int bssmap_handle_reset_ack(struct bsc_msc_data *msc, struct msgb *msg, unsigned int length) { LOGP(DMSC, LOGL_NOTICE, "RESET ACK from MSC: %s\n", osmo_sccp_addr_name(osmo_ss7_instance_find(msc->a.cs7_instance), &msc->a.msc_addr)); /* Inform the FSM that controls the RESET/RESET-ACK procedure * that we have successfully received the reset-ack message */ a_reset_ack_confirm(msc->a.reset); return 0; } /* Handle MSC sided reset */ static int bssmap_handle_reset(struct bsc_msc_data *msc, struct msgb *msg, unsigned int length) { LOGP(DMSC, LOGL_NOTICE, "RESET from MSC: %s\n", osmo_sccp_addr_name(osmo_ss7_instance_find(msc->a.cs7_instance), &msc->a.msc_addr)); /* Instruct the bsc to close all open sigtran connections and to * close all active channels on the BTS side as well */ osmo_bsc_sigtran_reset(msc); /* Drop all ongoing paging requests that this MSC has created on any BTS */ paging_flush_network(msc->network, msc); /* Inform the MSC that we have received the reset request and * that we acted accordingly */ osmo_bsc_sigtran_tx_reset_ack(msc); return 0; } /* Page a subscriber based on TMSI and LAC via the specified BTS. * The msc parameter is the MSC which issued the corresponding paging request. * Returns 1 if the paging request could be issued, 0 if not. * A negative return value indicates an error. */ static int page_subscriber(struct bsc_msc_data *msc, struct gsm_bts *bts, uint32_t tmsi, uint32_t lac, const char *mi_string, uint8_t chan_needed) { struct bsc_subscr *subscr; int ret; subscr = bsc_subscr_find_or_create_by_imsi(msc->network->bsc_subscribers, 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_INFO, "Paging request from MSC BTS: %d IMSI: '%s' TMSI: '0x%x/%u' LAC: 0x%x\n", bts->nr, mi_string, tmsi, tmsi, lac); ret = bsc_grace_paging_request(msc->network->bsc_data->rf_ctrl->policy, subscr, chan_needed, msc, bts); /* the paging code has grabbed its own references */ bsc_subscr_put(subscr); return ret; } /* Decode 5-byte LAI list element data (see TS 08.08 3.2.2.27) into MCC/MNC/LAC. * Return 0 if successful, negative on error. */ static int decode_lai(const uint8_t *data, uint16_t *mcc, uint16_t *mnc, uint16_t *lac) { struct gsm48_loc_area_id lai; /* Copy data to stack to prevent unaligned access in gsm48_decode_lai(). */ memcpy(&lai, data, sizeof(lai)); /* don't byte swap yet */ return gsm48_decode_lai(&lai, mcc, mnc, lac) != 0 ? -1 : 0; } static void page_all_bts(struct bsc_msc_data *msc, uint32_t tmsi, const char *mi_string, uint8_t chan_needed) { struct gsm_bts *bts; llist_for_each_entry(bts, &msc->network->bts_list, list) { /* ignore errors from page_subscriber(); try all BTS */ page_subscriber(msc, bts, tmsi, GSM_LAC_RESERVED_ALL_BTS, mi_string, chan_needed); } } static void page_cgi(struct bsc_msc_data *msc, const uint8_t *data, uint8_t data_length, size_t remain, uint32_t tmsi, const char *mi_string, uint8_t chan_needed) { uint16_t ci; int i = 0; while (remain >= sizeof(struct gsm48_loc_area_id) + sizeof(ci)) { uint16_t mcc, mnc, lac, *ci_be; size_t lai_offset = 1 + i * (sizeof(struct gsm48_loc_area_id) + sizeof(ci)); if (decode_lai(&data[lai_offset], &mcc, &mnc, &lac) != 0) { LOGP(DMSC, LOGL_ERROR, "Paging IMSI %s: Invalid LAI in Cell Identifier List " "for BSS (0x%x), paging entire BSS anyway (%s)\n", mi_string, CELL_IDENT_BSS, osmo_hexdump(data, data_length)); page_all_bts(msc, tmsi, mi_string, chan_needed); return; } ci_be = (uint16_t *)(&data[lai_offset + sizeof(struct gsm48_loc_area_id)]); ci = osmo_load16be(ci_be); if (mcc == msc->network->country_code && mnc == msc->network->network_code) { int paged = 0; struct gsm_bts *bts; llist_for_each_entry(bts, &msc->network->bts_list, list) { if (bts->location_area_code != lac) continue; if (bts->cell_identity != ci) continue; /* ignore errors from page_subscriber(); keep trying other BTS */ page_subscriber(msc, bts, tmsi, lac, mi_string, chan_needed); paged = 1; } if (!paged) { LOGP(DMSC, LOGL_NOTICE, "Paging IMSI %s: BTS with LAC %d and CI %d not found\n", mi_string, lac, ci); } } else { LOGP(DMSC, LOGL_DEBUG, "Paging IMSI %s: MCC/MNC in Cell Identifier List " "(%d/%d) do not match our network (%d/%d)\n", mi_string, mcc, mnc, msc->network->country_code, msc->network->network_code); } remain -= sizeof(struct gsm48_loc_area_id) + sizeof(ci); i++; } } static void page_lac_and_ci(struct bsc_msc_data *msc, const uint8_t *data, size_t remain, uint32_t tmsi, const char *mi_string, uint8_t chan_needed) { uint16_t *lacp_be, *ci_be; lacp_be = (uint16_t *)(&data[1]); ci_be = (uint16_t *)(&data[3]); while (remain >= sizeof(*lacp_be) + sizeof(*ci_be)) { uint16_t lac = osmo_load16be(lacp_be); uint16_t ci = osmo_load16be(ci_be); int paged = 0; struct gsm_bts *bts; llist_for_each_entry(bts, &msc->network->bts_list, list) { if (bts->location_area_code != lac) continue; if (bts->cell_identity != ci) continue; /* ignore errors from page_subscriber(); keep trying other BTS */ page_subscriber(msc, bts, tmsi, lac, mi_string, chan_needed); paged = 1; } if (!paged) { LOGP(DMSC, LOGL_NOTICE, "Paging IMSI %s: BTS with LAC %d and CI %d not found\n", mi_string, lac, ci); } remain -= sizeof(*lacp_be) + sizeof(*ci_be); lacp_be++; ci_be++; } } static void page_ci(struct bsc_msc_data *msc, const uint8_t *data, size_t remain, uint32_t tmsi, const char *mi_string, uint8_t chan_needed) { uint16_t *ci_be = (uint16_t *)(&data[1]); while (remain >= sizeof(*ci_be)) { uint16_t ci = osmo_load16be(ci_be); int paged = 0; struct gsm_bts *bts; llist_for_each_entry(bts, &msc->network->bts_list, list) { if (bts->cell_identity != ci) continue; /* ignore errors from page_subscriber(); keep trying other BTS */ page_subscriber(msc, bts, tmsi, GSM_LAC_RESERVED_ALL_BTS, mi_string, chan_needed); paged = 1; } if (!paged) { LOGP(DMSC, LOGL_NOTICE, "Paging IMSI %s: BTS with CI %d not found\n", mi_string, ci); } remain -= sizeof(*ci_be); ci_be++; } } static void page_lai_and_lac(struct bsc_msc_data *msc, const uint8_t *data, size_t data_length, size_t remain, uint32_t tmsi, const char *mi_string, uint8_t chan_needed) { int i = 0; while (remain >= sizeof(struct gsm48_loc_area_id)) { uint16_t mcc, mnc, lac; if (decode_lai(&data[1 + i * sizeof(struct gsm48_loc_area_id)], &mcc, &mnc, &lac) != 0) { LOGP(DMSC, LOGL_ERROR, "Paging IMSI %s: Invalid LAI in Cell Identifier List " "for BSS (0x%x), paging entire BSS anyway (%s)\n", mi_string, CELL_IDENT_BSS, osmo_hexdump(data, data_length)); page_all_bts(msc, tmsi, mi_string, chan_needed); return; } if (mcc == msc->network->country_code && mnc == msc->network->network_code) { int paged = 0; struct gsm_bts *bts; llist_for_each_entry(bts, &msc->network->bts_list, list) { if (bts->location_area_code != lac) continue; /* ignore errors from page_subscriber(); keep trying other BTS */ page_subscriber(msc, bts, tmsi, lac, mi_string, chan_needed); paged = 1; } if (!paged) { LOGP(DMSC, LOGL_NOTICE, "Paging IMSI %s: BTS with LAC %d not found\n", mi_string, lac); } } else { LOGP(DMSC, LOGL_DEBUG, "Paging IMSI %s: MCC/MNC in Cell Identifier List " "(%d/%d) do not match our network (%d/%d)\n", mi_string, mcc, mnc, msc->network->country_code, msc->network->network_code); } remain -= sizeof(struct gsm48_loc_area_id); i++; } } static void page_lac(struct bsc_msc_data *msc, const uint8_t *data, size_t remain, uint32_t tmsi, const char *mi_string, uint8_t chan_needed) { uint16_t *lacp_be = (uint16_t *)(&data[1]); while (remain >= sizeof(*lacp_be)) { uint16_t lac = osmo_load16be(lacp_be); int paged = 0; struct gsm_bts *bts; llist_for_each_entry(bts, &msc->network->bts_list, list) { if (bts->location_area_code != lac) continue; /* ignore errors from page_subscriber(); keep trying other BTS */ page_subscriber(msc, bts, tmsi, lac, mi_string, chan_needed); paged = 1; } if (!paged) { LOGP(DMSC, LOGL_NOTICE, "Paging IMSI %s: BTS with LAC %d not found\n", mi_string, lac); } remain -= sizeof(*lacp_be); lacp_be++; } } /* GSM 08.08 § 3.2.1.19 */ static int bssmap_handle_paging(struct bsc_msc_data *msc, struct msgb *msg, unsigned int payload_length) { struct tlv_parsed tp; char mi_string[GSM48_MI_SIZE]; uint32_t tmsi = GSM_RESERVED_TMSI; uint8_t data_length; int remain; const uint8_t *data; uint8_t chan_needed = RSL_CHANNEED_ANY; uint8_t cell_ident; tlv_parse(&tp, gsm0808_att_tlvdef(), msg->l4h + 1, payload_length - 1, 0, 0); remain = payload_length - 1; if (!TLVP_PRESENT(&tp, GSM0808_IE_IMSI)) { LOGP(DMSC, LOGL_ERROR, "Mandatory 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; } remain -= TLVP_LEN(&tp, GSM0808_IE_IMSI); if (!TLVP_PRESENT(&tp, GSM0808_IE_CELL_IDENTIFIER_LIST)) { LOGP(DMSC, LOGL_ERROR, "Mandatory CELL IDENTIFIER LIST not present.\n"); return -1; } if (TLVP_PRESENT(&tp, GSM0808_IE_TMSI) && TLVP_LEN(&tp, GSM0808_IE_TMSI) == 4) { tmsi = ntohl(tlvp_val32_unal(&tp, GSM0808_IE_TMSI)); remain -= TLVP_LEN(&tp, GSM0808_IE_TMSI); } if (remain <= 0) { LOGP(DMSC, LOGL_ERROR, "Payload too short.\n"); return -1; } /* * parse the IMSI */ gsm48_mi_to_string(mi_string, sizeof(mi_string), TLVP_VAL(&tp, GSM0808_IE_IMSI), TLVP_LEN(&tp, GSM0808_IE_IMSI)); /* * There are various cell identifier list types defined at 3GPP TS § 08.08, we don't support all * of them yet. To not disrupt paging operation just because we're lacking some implementation, * interpret any unknown cell identifier type as "page the entire BSS". */ data_length = TLVP_LEN(&tp, GSM0808_IE_CELL_IDENTIFIER_LIST); data = TLVP_VAL(&tp, GSM0808_IE_CELL_IDENTIFIER_LIST); if (data_length < 1) { LOGP(DMSC, LOGL_ERROR, "Paging IMSI %s: Zero length Cell Identifier List\n", mi_string); return -1; } else if (data_length > remain) { LOGP(DMSC, LOGL_ERROR, "Paging IMSI %s: Bogus Cell Identifier List length\n", mi_string); return -1; } remain = data_length; /* ignore payload padding data beyond data_length */ 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"); } cell_ident = data[0] & 0xf; remain -= 1; /* cell ident consumed */ switch (cell_ident) { case CELL_IDENT_NO_CELL: LOGP(DMSC, LOGL_NOTICE, "Ignoring no-op paging request for IMSI %s\n", mi_string); return 0; /* nothing to do */ case CELL_IDENT_WHOLE_GLOBAL: page_cgi(msc, data, data_length, remain, tmsi, mi_string, chan_needed); break; case CELL_IDENT_LAC_AND_CI: page_lac_and_ci(msc, data, remain, tmsi, mi_string, chan_needed); break; case CELL_IDENT_CI: page_ci(msc, data, remain, tmsi, mi_string, chan_needed); break; case CELL_IDENT_LAI_AND_LAC: page_lai_and_lac(msc, data, data_length, remain, tmsi, mi_string, chan_needed); break; case CELL_IDENT_LAC: page_lac(msc, data, remain, tmsi, mi_string, chan_needed); break; case CELL_IDENT_BSS: if (data_length != 1) { LOGP(DMSC, LOGL_ERROR, "Paging IMSI %s: Cell Identifier List for BSS (0x%x)" " has invalid length: %u, paging entire BSS anyway (%s)\n", mi_string, CELL_IDENT_BSS, data_length, osmo_hexdump(data, data_length)); } page_all_bts(msc, tmsi, mi_string, chan_needed); break; default: LOGP(DMSC, LOGL_NOTICE, "Paging IMSI %s: unimplemented Cell Identifier List (0x%x)," " paging entire BSS instead (%s)\n", mi_string, cell_ident, osmo_hexdump(data, data_length)); page_all_bts(msc, tmsi, mi_string, chan_needed); break; } 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 gsm_subscriber_connection *conn, struct msgb *msg, unsigned int payload_length) { struct msgb *resp; /* TODO: handle the cause of this package */ LOGP(DMSC, LOGL_INFO, "Releasing all transactions on %p\n", conn); gsm0808_clear(conn); /* generate the clear complete message */ resp = gsm0808_create_clear_complete(); if (!resp) { LOGP(DMSC, LOGL_ERROR, "Sending clear complete failed.\n"); return -1; } if (conn->user_plane.mgcp_ctx) { /* NOTE: This is the AoIP case, osmo-bsc has to negotiate with * the MGCP-GW. For this an mgcp_ctx should be created that * contains the FSM and some system data. When the connection * is removed from the MGCP-GW, then osmo_bsc_sigtran_send() * calls osmo_bsc_sigtran_send(). */ mgcp_clear_complete(conn->user_plane.mgcp_ctx, resp); } else { /* NOTE: This is the SCCP-Lite case, since we do not handle * the MGCP-GW switching ourselves, we may skip everything * that is MGCP-GW related and sent the clear complete message * directly */ osmo_bsc_sigtran_send(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 encryption or no encryption. */ static int bssmap_handle_cipher_mode(struct gsm_subscriber_connection *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; const uint8_t *enc_key; uint16_t enc_key_len; uint8_t enc_bits_bsc; uint8_t enc_bits_msc; if (!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_get_bts(conn)->network; data = TLVP_VAL(&tp, GSM0808_IE_ENCRYPTION_INFORMATION); enc_bits_msc = data[0]; enc_key = &data[1]; enc_key_len = len - 1; if (TLVP_PRESENT(&tp, GSM0808_IE_CIPHER_RESPONSE_MODE)) include_imeisv = TLVP_VAL(&tp, GSM0808_IE_CIPHER_RESPONSE_MODE)[0] & 0x1; /* FIXME: match up the list of permitted ciphering algorithms received from the MSC with a list * of ciphering algorithms configured for this BSC (the config of more than one is TODO). Finally * pick one of the remaining options. */ /* Identical to the GSM0808_IE_ENCRYPTION_INFORMATION above: * a5_encryption == 0 --> 0x01 * a5_encryption == 1 --> 0x02 * a5_encryption == 2 --> 0x04 ... */ enc_bits_bsc = 1 << network->a5_encryption; enc_bits_msc = data[0]; if (!(enc_bits_msc & enc_bits_bsc)) { LOGP(DMSC, LOGL_ERROR, "MSC does not permit A5/%d (permitted algorithms mask: 0x%x)\n", network->a5_encryption, enc_bits_msc); reject_cause = GSM0808_CAUSE_CIPHERING_ALGORITHM_NOT_SUPPORTED; goto reject; } /* To complete the confusion, gsm0808_cipher_mode again expects the encryption as a number * from 0 to 7. */ if (gsm0808_cipher_mode(conn, network->a5_encryption, enc_key, enc_key_len, include_imeisv)) { reject_cause = GSM0808_CAUSE_PROTOCOL_ERROR_BETWEEN_BSS_AND_MSC; goto reject; } return 0; reject: resp = gsm0808_create_cipher_reject(reject_cause); if (!resp) { LOGP(DMSC, LOGL_ERROR, "Sending the cipher reject failed.\n"); return -1; } osmo_bsc_sigtran_send(conn, resp); return -1; } /* Helper function to calculate the port number for a given * timeslot/multiplex. This functionality is needed to support * the sccp-lite scenario where the MGW is handled externally */ static inline int mgcp_timeslot_to_port(int multiplex, int timeslot, int base) { if (timeslot == 0) { LOGP(DLMGCP, LOGL_ERROR, "Timeslot should not be 0\n"); timeslot = 255; } return base + (timeslot + (32 * multiplex)) * 2; } /* * Handle the assignment request message. * * See §3.2.1.1 for the message type */ static int bssmap_handle_assignm_req(struct gsm_subscriber_connection *conn, struct msgb *msg, unsigned int length) { struct msgb *resp; struct bsc_msc_data *msc; struct tlv_parsed tp; uint8_t timeslot = 0; uint8_t multiplex = 0; enum gsm48_chan_mode chan_mode = GSM48_CMODE_SIGN; int full_rate = -1; bool aoip = false; struct sockaddr_storage rtp_addr; struct gsm0808_channel_type ct; struct gsm0808_speech_codec_list *scl_ptr = NULL; int rc; if (!conn) { LOGP(DMSC, LOGL_ERROR, "No lchan/msc_data in cipher mode command.\n"); return -1; } msc = conn->sccp.msc; tlv_parse(&tp, gsm0808_att_tlvdef(), msg->l4h + 1, length - 1, 0, 0); /* Check for channel type element, if its missing, immediately reject */ if (!TLVP_PRESENT(&tp, GSM0808_IE_CHANNEL_TYPE)) { LOGP(DMSC, LOGL_ERROR, "Mandatory channel type not present.\n"); goto reject; } /* Decode Channel Type element */ rc = gsm0808_dec_channel_type(&ct, TLVP_VAL(&tp, GSM0808_IE_CHANNEL_TYPE), TLVP_LEN(&tp, GSM0808_IE_CHANNEL_TYPE)); if (rc < 0) { LOGP(DMSC, LOGL_ERROR, "unable to decode channel type.\n"); goto reject; } /* Currently we only support a limited subset of all * possible channel types. The limitation ends by not using * multi-slot, limiting the channel coding to speech */ if (ct.ch_indctr != GSM0808_CHAN_SPEECH) { LOGP(DMSC, LOGL_ERROR, "Unsupported channel type, currently only speech is supported!\n"); goto reject; } /* Detect if a CIC code is present, if so, we use the classic ip.access * method to calculate the RTP port */ if (TLVP_PRESENT(&tp, GSM0808_IE_CIRCUIT_IDENTITY_CODE)) { conn->user_plane.cic = osmo_load16be(TLVP_VAL(&tp, GSM0808_IE_CIRCUIT_IDENTITY_CODE)); timeslot = conn->user_plane.cic & 0x1f; multiplex = (conn->user_plane.cic & ~0x1f) >> 5; } else if (TLVP_PRESENT(&tp, GSM0808_IE_AOIP_TRASP_ADDR)) { /* Decode AoIP transport address element */ rc = gsm0808_dec_aoip_trasp_addr(&rtp_addr, TLVP_VAL(&tp, GSM0808_IE_AOIP_TRASP_ADDR), TLVP_LEN(&tp, GSM0808_IE_AOIP_TRASP_ADDR)); if (rc < 0) { LOGP(DMSC, LOGL_ERROR, "Unable to decode aoip transport address.\n"); goto reject; } aoip = true; } else { LOGP(DMSC, LOGL_ERROR, "transport address missing. Audio routing will not work.\n"); goto reject; } /* Decode speech codec list (AoIP) */ conn->codec_list_present = false; if (aoip) { /* Check for speech codec list element */ if (!TLVP_PRESENT(&tp, GSM0808_IE_SPEECH_CODEC_LIST)) { LOGP(DMSC, LOGL_ERROR, "Mandatory speech codec list not present.\n"); goto reject; } /* Decode Speech Codec list */ rc = gsm0808_dec_speech_codec_list(&conn->codec_list, TLVP_VAL(&tp, GSM0808_IE_SPEECH_CODEC_LIST), TLVP_LEN(&tp, GSM0808_IE_SPEECH_CODEC_LIST)); if (rc < 0) { LOGP(DMSC, LOGL_ERROR, "Unable to decode speech codec list\n"); goto reject; } conn->codec_list_present = true; scl_ptr = &conn->codec_list; } /* Match codec information from the assignment command against the * local preferences of the BSC */ rc = match_codec_pref(&full_rate, &chan_mode, &ct, scl_ptr, msc); if (rc < 0) { LOGP(DMSC, LOGL_ERROR, "No supported audio type found for channel_type =" " { ch_indctr=0x%x, ch_rate_type=0x%x, perm_spch=[ %s] }\n", ct.ch_indctr, ct.ch_rate_type, osmo_hexdump(ct.perm_spch, ct.perm_spch_len)); /* TODO: actually output codec names, e.g. implement gsm0808_permitted_speech_names[] and * iterate perm_spch. */ goto reject; } DEBUGP(DMSC, "Found matching audio type: %s %s for channel_type =" " { ch_indctr=0x%x, ch_rate_type=0x%x, perm_spch=[ %s] }\n", full_rate? "full rate" : "half rate", get_value_string(gsm48_chan_mode_names, chan_mode), ct.ch_indctr, ct.ch_rate_type, osmo_hexdump(ct.perm_spch, ct.perm_spch_len)); /* Forward the assignment request to lower layers */ if (aoip) { /* Store network side RTP connection information, we will * process this address later after we have established an RTP * connection to the BTS. This is just for organizational * reasons, functional wise it would not matter when exactly * the network side RTP connection is made, as long it is made * before we return with the assignment complete message. */ memcpy(&conn->user_plane.aoip_rtp_addr_remote, &rtp_addr, sizeof(rtp_addr)); /* Create an assignment request using the MGCP fsm. This FSM * is directly started when its created (now) and will also * take care about the further processing (creating RTP * endpoints, calling gsm0808_assign_req(), responding to * the assignment request etc... */ conn->user_plane.mgcp_ctx = mgcp_assignm_req(msc->network, msc->network->mgw.client, conn, chan_mode, full_rate); if (!conn->user_plane.mgcp_ctx) { LOGP(DMSC, LOGL_ERROR, "MGCP GW failure, rejecting assignment... (id=%i)\n", conn->sccp.conn_id); goto reject; } /* We now may return here, the FSM will do all further work */ return 0; } else { /* Note: In the sccp-lite case we to not perform any mgcp operation, * (the MSC does that for us). We set conn->rtp_ip to 0 and check * on this later. By this we know that we have to behave accordingly * to sccp-lite. */ conn->user_plane.rtp_port = mgcp_timeslot_to_port(multiplex, timeslot, msc->rtp_base); conn->user_plane.rtp_ip = 0; return gsm0808_assign_req(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; } osmo_bsc_sigtran_send(conn, resp); return -1; } static int bssmap_rcvmsg_udt(struct bsc_msc_data *msc, struct msgb *msg, unsigned int length) { int ret = 0; if (length < 1) { LOGP(DMSC, LOGL_ERROR, "Not enough room: %d\n", length); return -1; } LOGP(DMSC, LOGL_INFO, "Rx MSC UDT BSSMAP %s\n", gsm0808_bssmap_name(msg->l4h[0])); switch (msg->l4h[0]) { case BSS_MAP_MSG_RESET_ACKNOWLEDGE: ret = bssmap_handle_reset_ack(msc, msg, length); break; case BSS_MAP_MSG_RESET: ret = bssmap_handle_reset(msc, msg, length); break; case BSS_MAP_MSG_PAGING: ret = bssmap_handle_paging(msc, msg, length); break; default: LOGP(DMSC, LOGL_NOTICE, "Received unimplemented BSSMAP UDT %s\n", gsm0808_bssmap_name(msg->l4h[0])); break; } return ret; } static int bssmap_rcvmsg_dt1(struct gsm_subscriber_connection *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; } LOGP(DMSC, LOGL_INFO, "Rx MSC DT1 BSSMAP %s\n", gsm0808_bssmap_name(msg->l4h[0])); 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_NOTICE, "Unimplemented msg type: %s\n", gsm0808_bssmap_name(msg->l4h[0])); break; } return ret; } static int dtap_rcvmsg(struct gsm_subscriber_connection *conn, struct msgb *msg, unsigned int length) { struct dtap_header *header; struct msgb *gsm48; uint8_t *data; int rc, dtap_rc; LOGP(DMSC, LOGL_DEBUG, "Rx MSC DTAP: %s\n", osmo_hexdump(msg->l3h, length)); if (!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: %zu 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_INFO, "Rx MSC DTAP, SAPI: %u CHAN: %u\n", header->link_id & 0x07, header->link_id & 0xC0); /* forward the data */ gsm48 = gsm48_msgb_alloc_name("GSM 04.08 DTAP RCV"); 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 */ rc = bsc_scan_msc_msg(conn, gsm48); dtap_rc = gsm0808_submit_dtap(conn, gsm48, header->link_id, 1); if (rc == BSS_SEND_USSD) bsc_send_welcome_ussd(conn); return dtap_rc; } int bsc_handle_udt(struct bsc_msc_data *msc, struct msgb *msgb, unsigned int length) { struct bssmap_header *bs; LOGP(DMSC, LOGL_DEBUG, "Rx MSC UDT: %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(msc, msgb, length - sizeof(*bs)); break; default: LOGP(DMSC, LOGL_NOTICE, "Unimplemented msg type: %s\n", gsm0808_bssmap_name(bs->type)); } return 0; } int bsc_handle_dt(struct gsm_subscriber_connection *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_NOTICE, "Unimplemented BSSAP msg type: %s\n", gsm0808_bssap_name(msg->l3h[0])); } return -1; } /* Generate and send assignment complete message */ int bssmap_send_aoip_ass_compl(struct gsm_lchan *lchan) { struct msgb *resp; struct gsm0808_speech_codec sc; struct gsm_subscriber_connection *conn; conn = lchan->conn; OSMO_ASSERT(lchan->abis_ip.ass_compl.valid); OSMO_ASSERT(conn); LOGP(DMSC, LOGL_DEBUG, "Sending assignment complete message... (id=%i)\n", conn->sccp.conn_id); /* Extrapolate speech codec from speech mode */ gsm0808_speech_codec_from_chan_type(&sc, lchan->abis_ip.ass_compl.speech_mode); /* Generate message */ resp = gsm0808_create_ass_compl(lchan->abis_ip.ass_compl.rr_cause, lchan->abis_ip.ass_compl.chosen_channel, lchan->abis_ip.ass_compl.encr_alg_id, lchan->abis_ip.ass_compl.speech_mode, &conn->user_plane.aoip_rtp_addr_local, &sc, NULL); if (!resp) { LOGP(DMSC, LOGL_ERROR, "Failed to generate assignment completed message! (id=%i)\n", conn->sccp.conn_id); return -EINVAL; } return osmo_bsc_sigtran_send(conn, resp); }