diff options
Diffstat (limited to 'src/libmsc/a_iface_bssap.c')
-rw-r--r-- | src/libmsc/a_iface_bssap.c | 717 |
1 files changed, 717 insertions, 0 deletions
diff --git a/src/libmsc/a_iface_bssap.c b/src/libmsc/a_iface_bssap.c new file mode 100644 index 000000000..561ccdeb0 --- /dev/null +++ b/src/libmsc/a_iface_bssap.c @@ -0,0 +1,717 @@ +/* (C) 2017 by Sysmocom s.f.m.c. GmbH + * All Rights Reserved + * + * Author: Philipp Maier + * + * 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 <osmocom/core/utils.h> +#include <osmocom/core/msgb.h> +#include <osmocom/core/logging.h> +#include <osmocom/sigtran/sccp_helpers.h> +#include <osmocom/sccp/sccp_types.h> +#include <osmocom/gsm/gsm0808.h> +#include <osmocom/gsm/gsm0808_utils.h> +#include <openbsc/debug.h> +#include <openbsc/gsm_data.h> +#include <openbsc/a_iface_bssap.h> +#include <openbsc/a_iface.h> +#include <openbsc/iu.h> +#include <openbsc/osmo_msc.h> +#include <osmocom/core/byteswap.h> +#include <openbsc/a_reset.h> + +#define IP_V4_ADDR_LEN 4 + +/* + * Helper functions to lookup and allocate subscribers + */ + +/* Allocate a new subscriber connection */ +static struct gsm_subscriber_connection *subscr_conn_allocate_a(const struct a_conn_info *a_conn_info, + struct gsm_network *network, + uint16_t lac, struct osmo_sccp_user *scu, int conn_id) +{ + struct gsm_subscriber_connection *conn; + + LOGP(DMSC, LOGL_NOTICE, "Allocating A-Interface subscriber conn: lac %i, conn_id %i\n", lac, conn_id); + + conn = talloc_zero(network, struct gsm_subscriber_connection); + if (!conn) + return NULL; + + conn->network = network; + conn->via_ran = RAN_GERAN_A; + conn->lac = lac; + + conn->a.conn_id = conn_id; + conn->a.scu = scu; + + /* Also backup the calling address of the BSC, this allows us to + * identify later which BSC is responsible for this subscriber connection */ + memcpy(&conn->a.bsc_addr, a_conn_info->bsc_addr, sizeof(conn->a.bsc_addr)); + + llist_add_tail(&conn->entry, &network->subscr_conns); + LOGP(DMSC, LOGL_NOTICE, "A-Interface subscriber connection successfully allocated!\n"); + return conn; +} + +/* Return an existing A subscriber connection record for the given + * connection IDs, or return NULL if not found. */ +static struct gsm_subscriber_connection *subscr_conn_lookup_a(const struct gsm_network *network, int conn_id) +{ + struct gsm_subscriber_connection *conn; + + OSMO_ASSERT(network); + + DEBUGP(DMSC, "Looking for A subscriber: conn_id %i\n", conn_id); + + /* FIXME: log_subscribers() is defined in iucs.c as static inline, if + * maybe this function should be public to reach it from here? */ + /* log_subscribers(network); */ + + llist_for_each_entry(conn, &network->subscr_conns, entry) { + if (conn->via_ran == RAN_GERAN_A && conn->a.conn_id == conn_id) { + DEBUGP(DIUCS, "Found A subscriber for conn_id %i\n", conn_id); + return conn; + } + } + DEBUGP(DMSC, "No A subscriber found for conn_id %i\n", conn_id); + return NULL; +} + +/* + * BSSMAP handling for UNITDATA + */ + +/* Endpoint to handle BSSMAP reset */ +static void bssmap_rx_reset(struct osmo_sccp_user *scu, const struct a_conn_info *a_conn_info, struct msgb *msg) +{ + struct gsm_network *network = a_conn_info->network; + struct osmo_ss7_instance *ss7; + + ss7 = osmo_ss7_instance_find(network->a.cs7_instance); + OSMO_ASSERT(ss7); + + LOGP(DMSC, LOGL_NOTICE, "Rx RESET from BSC %s, sending RESET ACK\n", + osmo_sccp_addr_name(ss7, a_conn_info->bsc_addr)); + osmo_sccp_tx_unitdata_msg(scu, a_conn_info->msc_addr, a_conn_info->bsc_addr, gsm0808_create_reset_ack()); + + /* Make sure all orphand subscriber connections will be cleard */ + a_clear_all(scu, a_conn_info->bsc_addr); + + msgb_free(msg); +} + +/* Endpoint to handle BSSMAP reset acknowlegement */ +static void bssmap_rx_reset_ack(const struct osmo_sccp_user *scu, const struct a_conn_info *a_conn_info, + struct msgb *msg) +{ + + struct gsm_network *network = a_conn_info->network; + struct osmo_ss7_instance *ss7; + + ss7 = osmo_ss7_instance_find(network->a.cs7_instance); + OSMO_ASSERT(ss7); + + if (a_conn_info->reset == NULL) { + LOGP(DMSC, LOGL_ERROR, "Received RESET ACK from an unknown BSC %s, ignoring...\n", + osmo_sccp_addr_name(ss7, a_conn_info->bsc_addr)); + goto fail; + } + + LOGP(DMSC, LOGL_NOTICE, "Received RESET ACK from BSC %s\n", osmo_sccp_addr_name(ss7, a_conn_info->bsc_addr)); + + /* Confirm that we managed to get the reset ack message + * towards the connection reset logic */ + a_reset_ack_confirm(a_conn_info->reset); + +fail: + msgb_free(msg); +} + +/* Handle UNITDATA BSSMAP messages */ +static void bssmap_rcvmsg_udt(struct osmo_sccp_user *scu, const struct a_conn_info *a_conn_info, struct msgb *msg) +{ + /* Note: When in the MSC role, RESET ACK is the only valid message that + * can be received via UNITDATA */ + + if (msgb_l3len(msg) < 1) { + LOGP(DMSC, LOGL_NOTICE, "Error: No data received -- discarding message!\n"); + return; + } + + LOGP(DMSC, LOGL_NOTICE, "Rx BSC UDT BSSMAP %s\n", gsm0808_bssmap_name(msg->l3h[0])); + + switch (msg->l3h[0]) { + case BSS_MAP_MSG_RESET: + bssmap_rx_reset(scu, a_conn_info, msg); + break; + case BSS_MAP_MSG_RESET_ACKNOWLEDGE: + bssmap_rx_reset_ack(scu, a_conn_info, msg); + break; + default: + LOGP(DMSC, LOGL_NOTICE, "Unimplemented message format: %s -- message discarded!\n", + gsm0808_bssmap_name(msg->l3h[0])); + msgb_free(msg); + } +} + +/* Receive incoming connection less data messages via sccp */ +void sccp_rx_udt(struct osmo_sccp_user *scu, const struct a_conn_info *a_conn_info, struct msgb *msg) +{ + /* Note: The only valid message type that can be received + * via UNITDATA are BSS Management messages */ + struct bssmap_header *bs; + + OSMO_ASSERT(scu); + OSMO_ASSERT(a_conn_info); + OSMO_ASSERT(msg); + + LOGP(DMSC, LOGL_NOTICE, "Rx BSC UDT: %s\n", osmo_hexdump(msgb_l2(msg), msgb_l2len(msg))); + + if (msgb_l2len(msg) < sizeof(*bs)) { + LOGP(DMSC, LOGL_ERROR, "Error: Header is too short -- discarding message!\n"); + msgb_free(msg); + return; + } + + bs = (struct bssmap_header *)msgb_l2(msg); + if (bs->length < msgb_l2len(msg) - sizeof(*bs)) { + LOGP(DMSC, LOGL_ERROR, "Error: Message is too short -- discarding message!\n"); + msgb_free(msg); + return; + } + + switch (bs->type) { + case BSSAP_MSG_BSS_MANAGEMENT: + msg->l3h = &msg->l2h[sizeof(struct bssmap_header)]; + bssmap_rcvmsg_udt(scu, a_conn_info, msg); + break; + default: + LOGP(DMSC, LOGL_ERROR, + "Error: Unimplemented message type: %s -- message discarded!\n", gsm0808_bssmap_name(bs->type)); + msgb_free(msg); + } +} + +/* + * BSSMAP handling for connection oriented data + */ + +/* Endpoint to handle BSSMAP clear request */ +static int bssmap_rx_clear_rqst(struct osmo_sccp_user *scu, const struct a_conn_info *a_conn_info, struct msgb *msg) +{ + struct gsm_network *network = a_conn_info->network; + struct tlv_parsed tp; + int rc; + struct msgb *msg_resp; + uint8_t cause; + struct gsm_subscriber_connection *conn; + + LOGP(DMSC, LOGL_NOTICE, "BSC requested to clear connection (conn_id=%i)\n", a_conn_info->conn_id); + + tlv_parse(&tp, gsm0808_att_tlvdef(), msg->l3h + 1, msgb_l3len(msg) - 1, 0, 0); + if (!TLVP_PRESENT(&tp, GSM0808_IE_CAUSE)) { + LOGP(DMSC, LOGL_ERROR, "Cause code is missing -- discarding message!\n"); + goto fail; + } + cause = TLVP_VAL(&tp, GSM0808_IE_CAUSE)[0]; + + /* Respond with clear command */ + msg_resp = gsm0808_create_clear_command(GSM0808_CAUSE_CALL_CONTROL); + rc = osmo_sccp_tx_data_msg(scu, a_conn_info->conn_id, msg_resp); + + /* If possible, inform the MSC about the clear request */ + conn = subscr_conn_lookup_a(network, a_conn_info->conn_id); + if (!conn) + goto fail; + msc_clear_request(conn, cause); + + msgb_free(msg); + return rc; + +fail: + msgb_free(msg); + return -EINVAL; +} + +/* Endpoint to handle BSSMAP clear complete */ +static int bssmap_rx_clear_complete(struct osmo_sccp_user *scu, const struct a_conn_info *a_conn_info, struct msgb *msg) +{ + int rc; + + LOGP(DMSC, LOGL_NOTICE, "Releasing connection (conn_id=%i)\n", a_conn_info->conn_id); + rc = osmo_sccp_tx_disconn(scu, a_conn_info->conn_id, + a_conn_info->msc_addr, SCCP_RELEASE_CAUSE_END_USER_ORIGINATED); + + /* Remove the record from the list with active connections. */ + a_delete_bsc_con(a_conn_info->conn_id); + + msgb_free(msg); + return rc; +} + +/* Endpoint to handle layer 3 complete messages */ +static int bssmap_rx_l3_compl(struct osmo_sccp_user *scu, const struct a_conn_info *a_conn_info, struct msgb *msg) +{ + struct tlv_parsed tp; + struct { + uint8_t ident; + struct gsm48_loc_area_id lai; + uint16_t ci; + } __attribute__ ((packed)) lai_ci; + uint16_t mcc; + uint16_t mnc; + uint16_t lac; + uint8_t data_length; + const uint8_t *data; + int rc; + + struct gsm_network *network = a_conn_info->network; + struct gsm_subscriber_connection *conn; + + LOGP(DMSC, LOGL_NOTICE, "BSC has completed layer 3 connection (conn_id=%i)\n", a_conn_info->conn_id); + + tlv_parse(&tp, gsm0808_att_tlvdef(), msg->l3h + 1, msgb_l3len(msg) - 1, 0, 0); + if (!TLVP_PRESENT(&tp, GSM0808_IE_CELL_IDENTIFIER)) { + LOGP(DMSC, LOGL_ERROR, "Mandatory CELL IDENTIFIER not present -- discarding message!\n"); + goto fail; + } + if (!TLVP_PRESENT(&tp, GSM0808_IE_LAYER_3_INFORMATION)) { + LOGP(DMSC, LOGL_ERROR, "Mandatory LAYER 3 INFORMATION not present -- discarding message!\n"); + goto fail; + } + + /* Parse Cell ID element */ + /* FIXME: Encapsulate this in a parser/generator function inside + * libosmocore, add support for all specified cell identification + * discriminators (see 3GPP ts 3.2.2.17 Cell Identifier) */ + data_length = TLVP_LEN(&tp, GSM0808_IE_CELL_IDENTIFIER); + data = TLVP_VAL(&tp, GSM0808_IE_CELL_IDENTIFIER); + if (sizeof(lai_ci) != data_length) { + LOGP(DMSC, LOGL_ERROR, + "Unable to parse element CELL IDENTIFIER (wrong field length) -- discarding message!\n"); + goto fail; + } + memcpy(&lai_ci, data, sizeof(lai_ci)); + if (lai_ci.ident != CELL_IDENT_WHOLE_GLOBAL) { + LOGP(DMSC, LOGL_ERROR, + "Unable to parse element CELL IDENTIFIER (wrong cell identification discriminator) -- discarding message!\n"); + goto fail; + } + if (gsm48_decode_lai(&lai_ci.lai, &mcc, &mnc, &lac) != 0) { + LOGP(DMSC, LOGL_ERROR, + "Unable to parse element CELL IDENTIFIER (lai decoding failed) -- discarding message!\n"); + goto fail; + } + + /* Parse Layer 3 Information element */ + /* FIXME: This is probably to hackish, compiler also complains "assignment discards ‘const’ qualifier..." */ + msg->l3h = TLVP_VAL(&tp, GSM0808_IE_LAYER_3_INFORMATION); + msg->tail = msg->l3h + TLVP_LEN(&tp, GSM0808_IE_LAYER_3_INFORMATION); + + /* Create new subscriber context */ + conn = subscr_conn_allocate_a(a_conn_info, network, lac, scu, a_conn_info->conn_id); + + /* Handover location update to the MSC code */ + /* msc_compl_l3() takes ownership of dtap_msg + * message buffer */ + rc = msc_compl_l3(conn, msg, 0); + if (rc == MSC_CONN_ACCEPT) { + LOGP(DMSC, LOGL_NOTICE, "User has been accepted by MSC.\n"); + return 0; + } else if (rc == MSC_CONN_REJECT) + LOGP(DMSC, LOGL_NOTICE, "User has been rejected by MSC.\n"); + else + LOGP(DMSC, LOGL_NOTICE, "User has been rejected by MSC (unknown error)\n"); + + return -EINVAL; + +fail: + msgb_free(msg); + return -EINVAL; +} + +/* Endpoint to handle BSSMAP classmark update */ +static int bssmap_rx_classmark_upd(struct osmo_sccp_user *scu, const struct a_conn_info *a_conn_info, struct msgb *msg) +{ + struct gsm_network *network = a_conn_info->network; + struct gsm_subscriber_connection *conn; + struct tlv_parsed tp; + const uint8_t *cm2 = NULL; + const uint8_t *cm3 = NULL; + uint8_t cm2_len = 0; + uint8_t cm3_len = 0; + + conn = subscr_conn_lookup_a(network, a_conn_info->conn_id); + if (!conn) + goto fail; + + LOGP(DMSC, LOGL_NOTICE, "BSC sends clasmark update (conn_id=%i)\n", conn->a.conn_id); + + tlv_parse(&tp, gsm0808_att_tlvdef(), msg->l3h + 1, msgb_l3len(msg) - 1, 0, 0); + if (!TLVP_PRESENT(&tp, GSM0808_IE_CLASSMARK_INFORMATION_T2)) { + LOGP(DMSC, LOGL_ERROR, "Mandatory Classmark Information Type 2 not present -- discarding message!\n"); + goto fail; + } + + cm2 = TLVP_VAL(&tp, GSM0808_IE_CLASSMARK_INFORMATION_T2); + cm2_len = TLVP_LEN(&tp, GSM0808_IE_CLASSMARK_INFORMATION_T2); + + if (TLVP_PRESENT(&tp, GSM0808_IE_CLASSMARK_INFORMATION_T3)) { + cm3 = TLVP_VAL(&tp, GSM0808_IE_CLASSMARK_INFORMATION_T3); + cm3_len = TLVP_LEN(&tp, GSM0808_IE_CLASSMARK_INFORMATION_T3); + } + + /* Inform MSC about the classmark change */ + msc_classmark_chg(conn, cm2, cm2_len, cm3, cm3_len); + + msgb_free(msg); + return 0; + +fail: + msgb_free(msg); + return -EINVAL; +} + +/* Endpoint to handle BSSMAP cipher mode complete */ +static int bssmap_rx_ciph_compl(const struct osmo_sccp_user *scu, const struct a_conn_info *a_conn_info, + struct msgb *msg) +{ + /* FIXME: The field GSM0808_IE_LAYER_3_MESSAGE_CONTENTS is optional by + * means of the specification. So there can be messages without L3 info. + * In this case, the code will crash becrause msc_cipher_mode_compl() + * is not able to deal with msg = NULL and apperently + * msc_cipher_mode_compl() was never meant to be used without L3 data. + * This needs to be discussed further! */ + + struct gsm_network *network = a_conn_info->network; + struct gsm_subscriber_connection *conn; + struct tlv_parsed tp; + uint8_t alg_id = 1; + + conn = subscr_conn_lookup_a(network, a_conn_info->conn_id); + if (!conn) + goto fail; + + LOGP(DMSC, LOGL_NOTICE, "BSC sends cipher mode complete (conn_id=%i)\n", conn->a.conn_id); + + tlv_parse(&tp, gsm0808_att_tlvdef(), msg->l3h + 1, msgb_l3len(msg) - 1, 0, 0); + + if (TLVP_PRESENT(&tp, GSM0808_IE_CHOSEN_ENCR_ALG)) { + alg_id = TLVP_VAL(&tp, GSM0808_IE_CHOSEN_ENCR_ALG)[0] - 1; + } + + if (TLVP_PRESENT(&tp, GSM0808_IE_LAYER_3_MESSAGE_CONTENTS)) { + msg->l3h = TLVP_VAL(&tp, GSM0808_IE_LAYER_3_MESSAGE_CONTENTS); + msg->tail = msg->l3h + TLVP_LEN(&tp, GSM0808_IE_LAYER_3_MESSAGE_CONTENTS); + } else { + msgb_free(msg); + msg = NULL; + } + + /* Hand over cipher mode complete message to the MSC, + * msc_cipher_mode_compl() takes ownership for msg */ + msc_cipher_mode_compl(conn, msg, alg_id); + + return 0; +fail: + msgb_free(msg); + return -EINVAL; +} + +/* Endpoint to handle BSSMAP cipher mode reject */ +static int bssmap_rx_ciph_rej(const struct osmo_sccp_user *scu, const struct a_conn_info *a_conn_info, struct msgb *msg) +{ + struct gsm_network *network = a_conn_info->network; + struct gsm_subscriber_connection *conn; + struct tlv_parsed tp; + uint8_t cause; + + conn = subscr_conn_lookup_a(network, a_conn_info->conn_id); + if (!conn) + goto fail; + + LOGP(DMSC, LOGL_NOTICE, "BSC sends cipher mode reject (conn_id=%i)\n", conn->a.conn_id); + + tlv_parse(&tp, gsm0808_att_tlvdef(), msg->l3h + 1, msgb_l3len(msg) - 1, 0, 0); + if (!TLVP_PRESENT(&tp, BSS_MAP_MSG_CIPHER_MODE_REJECT)) { + LOGP(DMSC, LOGL_ERROR, "Cause code is missing -- discarding message!\n"); + goto fail; + } + + cause = TLVP_VAL(&tp, BSS_MAP_MSG_CIPHER_MODE_REJECT)[0]; + LOGP(DMSC, LOGL_NOTICE, "Cipher mode rejection cause: %i\n", cause); + + /* FIXME: Can we do something meaningful here? e.g. report to the + * msc code somehow that the cipher mode command has failed. */ + + msgb_free(msg); + return 0; +fail: + msgb_free(msg); + return -EINVAL; +} + +/* Endpoint to handle BSSMAP assignment failure */ +static int bssmap_rx_ass_fail(const struct osmo_sccp_user *scu, const struct a_conn_info *a_conn_info, struct msgb *msg) +{ + struct gsm_network *network = a_conn_info->network; + struct gsm_subscriber_connection *conn; + struct tlv_parsed tp; + uint8_t cause; + uint8_t *rr_cause_ptr = NULL; + uint8_t rr_cause; + + conn = subscr_conn_lookup_a(network, a_conn_info->conn_id); + if (!conn) + goto fail; + + LOGP(DMSC, LOGL_NOTICE, "BSC sends assignment failure message (conn_id=%i)\n", conn->a.conn_id); + + tlv_parse(&tp, gsm0808_att_tlvdef(), msg->l3h + 1, msgb_l3len(msg) - 1, 0, 0); + if (!TLVP_PRESENT(&tp, GSM0808_IE_CAUSE)) { + LOGP(DMSC, LOGL_ERROR, "Cause code is missing -- discarding message!\n"); + goto fail; + } + cause = TLVP_VAL(&tp, GSM0808_IE_CAUSE)[0]; + + if (TLVP_PRESENT(&tp, GSM0808_IE_RR_CAUSE)) { + rr_cause = TLVP_VAL(&tp, GSM0808_IE_RR_CAUSE)[0]; + rr_cause_ptr = &rr_cause; + } + + /* FIXME: In AoIP, the Assignment failure will carry also an optional + * Codec List (BSS Supported) element. It has to be discussed if we + * can ignore this element. If not, The msc_assign_fail() function + * call has to change. However msc_assign_fail() does nothing in the + * end. So probably we can just leave it as it is. Even for AoIP */ + + /* Inform the MSC about the assignment failure event */ + msc_assign_fail(conn, cause, rr_cause_ptr); + + msgb_free(msg); + return 0; +fail: + msgb_free(msg); + return -EINVAL; +} + +/* Endpoint to handle sapi "n" reject */ +static int bssmap_rx_sapi_n_rej(const struct osmo_sccp_user *scu, const struct a_conn_info *a_conn_info, + struct msgb *msg) +{ + struct gsm_network *network = a_conn_info->network; + struct gsm_subscriber_connection *conn; + struct tlv_parsed tp; + uint8_t dlci; + + conn = subscr_conn_lookup_a(network, a_conn_info->conn_id); + if (!conn) + goto fail; + + LOGP(DMSC, LOGL_NOTICE, "BSC sends sapi \"n\" reject message (conn_id=%i)\n", conn->a.conn_id); + + /* Note: The MSC code seems not to care about the cause code, but by + * the specification it is mandatory, so we check its presence. See + * also 3GPP TS 48.008 3.2.1.34 SAPI "n" REJECT */ + tlv_parse(&tp, gsm0808_att_tlvdef(), msg->l3h + 1, msgb_l3len(msg) - 1, 0, 0); + if (!TLVP_PRESENT(&tp, GSM0808_IE_CAUSE)) { + LOGP(DMSC, LOGL_ERROR, "Cause code is missing -- discarding message!\n"); + goto fail; + } + + tlv_parse(&tp, gsm0808_att_tlvdef(), msg->l3h + 1, msgb_l3len(msg) - 1, 0, 0); + if (!TLVP_PRESENT(&tp, GSM0808_IE_DLCI)) { + LOGP(DMSC, LOGL_ERROR, "DLCI is missing -- discarding message!\n"); + goto fail; + } + dlci = TLVP_VAL(&tp, GSM0808_IE_DLCI)[0]; + + /* Inform the MSC about the sapi "n" reject event */ + msc_sapi_n_reject(conn, dlci); + + msgb_free(msg); + return 0; +fail: + msgb_free(msg); + return -EINVAL; +} + +/* Endpoint to handle assignment complete */ +static int bssmap_rx_ass_compl(const struct osmo_sccp_user *scu, const struct a_conn_info *a_conn_info, + struct msgb *msg) +{ + struct gsm_network *network = a_conn_info->network; + struct gsm_subscriber_connection *conn; + struct mgcpgw_client *mgcp; + struct tlv_parsed tp; + struct sockaddr_storage rtp_addr; + struct sockaddr_in *rtp_addr_in; + int rc; + + conn = subscr_conn_lookup_a(network, a_conn_info->conn_id); + if (!conn) + goto fail; + + mgcp = conn->network->mgcpgw.client; + OSMO_ASSERT(mgcp); + + LOGP(DMSC, LOGL_NOTICE, "BSC sends assignment complete message (conn_id=%i)\n", conn->a.conn_id); + + tlv_parse(&tp, gsm0808_att_tlvdef(), msg->l3h + 1, msgb_l3len(msg) - 1, 0, 0); + + if (!TLVP_PRESENT(&tp, GSM0808_IE_AOIP_TRASP_ADDR)) { + LOGP(DMSC, LOGL_ERROR, "AoIP transport identifier missing -- discarding message!\n"); + goto fail; + } + + /* 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 fail; + } + + /* use address / port supplied with the AoIP + * transport address element */ + if (rtp_addr.ss_family == AF_INET) { + rtp_addr_in = (struct sockaddr_in *)&rtp_addr; + conn->rtp.port_subscr = osmo_ntohs(rtp_addr_in->sin_port); + /* FIXME: We also get the IP-Address of the remote (e.g. BTS) + * end with the response. Currently we just ignore that address. + * Instead we expect that our local MGCP gateway and the code + * controlling it, magically knows the IP of the remote end. */ + } else { + LOGP(DMSC, LOGL_ERROR, "Unsopported addressing scheme. (supports only IPV4)\n"); + goto fail; + } + + /* FIXME: Seems to be related to authentication or, + encryption. Is this really in the right place? */ + msc_rx_sec_mode_compl(conn); + + msgb_free(msg); + return 0; +fail: + msgb_free(msg); + return -EINVAL; +} + +/* Handle incoming connection oriented BSSMAP messages */ +static int rx_bssmap(struct osmo_sccp_user *scu, const struct a_conn_info *a_conn_info, struct msgb *msg) +{ + if (msgb_l3len(msg) < 1) { + LOGP(DMSC, LOGL_NOTICE, "Error: No data received -- discarding message!\n"); + msgb_free(msg); + return -1; + } + + LOGP(DMSC, LOGL_NOTICE, "Rx MSC DT1 BSSMAP %s\n", gsm0808_bssmap_name(msg->l3h[0])); + + switch (msg->l3h[0]) { + case BSS_MAP_MSG_CLEAR_RQST: + return bssmap_rx_clear_rqst(scu, a_conn_info, msg); + break; + case BSS_MAP_MSG_CLEAR_COMPLETE: + return bssmap_rx_clear_complete(scu, a_conn_info, msg); + break; + case BSS_MAP_MSG_COMPLETE_LAYER_3: + return bssmap_rx_l3_compl(scu, a_conn_info, msg); + break; + case BSS_MAP_MSG_CLASSMARK_UPDATE: + return bssmap_rx_classmark_upd(scu, a_conn_info, msg); + break; + case BSS_MAP_MSG_CIPHER_MODE_COMPLETE: + return bssmap_rx_ciph_compl(scu, a_conn_info, msg); + break; + case BSS_MAP_MSG_CIPHER_MODE_REJECT: + return bssmap_rx_ciph_rej(scu, a_conn_info, msg); + break; + case BSS_MAP_MSG_ASSIGMENT_FAILURE: + return bssmap_rx_ass_fail(scu, a_conn_info, msg); + break; + case BSS_MAP_MSG_SAPI_N_REJECT: + return bssmap_rx_sapi_n_rej(scu, a_conn_info, msg); + break; + case BSS_MAP_MSG_ASSIGMENT_COMPLETE: + return bssmap_rx_ass_compl(scu, a_conn_info, msg); + break; + default: + LOGP(DMSC, LOGL_ERROR, "Unimplemented msg type: %s\n", gsm0808_bssmap_name(msg->l3h[0])); + msgb_free(msg); + return -EINVAL; + } + + return -EINVAL; +} + +/* Endpoint to handle regular BSSAP DTAP messages */ +static int rx_dtap(const struct osmo_sccp_user *scu, const struct a_conn_info *a_conn_info, struct msgb *msg) +{ + struct gsm_network *network = a_conn_info->network; + struct gsm_subscriber_connection *conn; + + conn = subscr_conn_lookup_a(network, a_conn_info->conn_id); + if (!conn) { + msgb_free(msg); + return -EINVAL; + } + + LOGP(DMSC, LOGL_NOTICE, "BSC sends layer 3 dtap (conn_id=%i)\n", conn->a.conn_id); + + /* msc_dtap expects the dtap payload in l3h */ + msg->l3h = msg->l2h + 3; + + /* Forward dtap payload into the msc, + * msc_dtap() takes ownership for msg */ + msc_dtap(conn, conn->a.conn_id, msg); + + return 0; +} + +/* Handle incoming connection oriented messages */ +int sccp_rx_dt(struct osmo_sccp_user *scu, const struct a_conn_info *a_conn_info, struct msgb *msg) +{ + OSMO_ASSERT(scu); + OSMO_ASSERT(a_conn_info); + OSMO_ASSERT(msg); + + LOGP(DMSC, LOGL_NOTICE, "Rx BSC DT: %s\n", osmo_hexdump(msgb_l2(msg), msgb_l2len(msg))); + + if (msgb_l2len(msg) < sizeof(struct bssmap_header)) { + LOGP(DMSC, LOGL_NOTICE, "The header is too short -- discarding message!\n"); + msgb_free(msg); + } + + switch (msg->l2h[0]) { + case BSSAP_MSG_BSS_MANAGEMENT: + msg->l3h = &msg->l2h[sizeof(struct bssmap_header)]; + return rx_bssmap(scu, a_conn_info, msg); + break; + case BSSAP_MSG_DTAP: + return rx_dtap(scu, a_conn_info, msg); + break; + default: + LOGP(DMSC, LOGL_ERROR, "Unimplemented BSSAP msg type: %s\n", gsm0808_bssap_name(msg->l2h[0])); + msgb_free(msg); + return -EINVAL; + } + + return -EINVAL; +} |