diff options
Diffstat (limited to 'src/libmsc/ran_msg_a.c')
-rw-r--r-- | src/libmsc/ran_msg_a.c | 1284 |
1 files changed, 1284 insertions, 0 deletions
diff --git a/src/libmsc/ran_msg_a.c b/src/libmsc/ran_msg_a.c new file mode 100644 index 000000000..2e498a28b --- /dev/null +++ b/src/libmsc/ran_msg_a.c @@ -0,0 +1,1284 @@ +/* BSSAP/BSSMAP encoding and decoding for MSC */ +/* + * (C) 2019 by sysmocom - s.m.f.c. GmbH <info@sysmocom.de> + * All Rights Reserved + * + * Author: Neels Hofmeyr + * + * SPDX-License-Identifier: GPL-2.0+ + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 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 General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +#include <osmocom/core/byteswap.h> + +#include <osmocom/crypt/auth.h> + +#include <osmocom/gsm/tlv.h> +#include <osmocom/gsm/gsm0808.h> +#include <osmocom/gsm/mncc.h> +#include <osmocom/gsm/gsm48.h> + +#include <osmocom/msc/debug.h> +#include <osmocom/msc/ran_msg_a.h> +#include <osmocom/msc/sccp_ran.h> + +#define LOG_RAN_A_DEC(RAN_DEC, level, fmt, args...) \ + LOG_RAN_DEC(RAN_DEC, DBSSAP, level, "BSSMAP: " fmt, ## args) + +/* Assumes presence of struct ran_dec *ran_dec and ran_dec_msg.msg_name (set) in the local scope. */ +#define LOG_RAN_A_DEC_MSG(level, fmt, args...) \ + LOG_RAN_DEC(ran_dec, DBSSAP, level, "%s: " fmt, ran_dec_msg.msg_name, ## args) + +#define LOG_RAN_A_ENC(FI, level, fmt, args...) \ + LOG_RAN_ENC(FI, DBSSAP, level, "BSSMAP: " fmt, ## args) + +static int ran_a_decode_l3_compl(struct ran_dec *ran_dec, struct msgb *msg, struct tlv_parsed *tp) +{ + struct gsm0808_cell_id_list2 cil; + struct gsm0808_cell_id cell_id; + struct tlv_p_entry *ie_cell_id = TLVP_GET(tp, GSM0808_IE_CELL_IDENTIFIER); + struct tlv_p_entry *ie_l3_info = TLVP_GET(tp, GSM0808_IE_LAYER_3_INFORMATION); + struct ran_msg ran_dec_msg = { + .msg_type = RAN_MSG_COMPL_L3, + .msg_name = "BSSMAP Complete Layer 3", + .compl_l3 = { + .cell_id = &cell_id, + .msg = msg, + }, + }; + int rc; + + if (!ie_cell_id) { + LOG_RAN_A_DEC_MSG(LOGL_ERROR, "Mandatory CELL IDENTIFIER not present, discarding message\n"); + return -EINVAL; + } + if (!ie_l3_info) { + LOG_RAN_A_DEC_MSG(LOGL_ERROR, "Mandatory LAYER 3 INFORMATION not present, discarding message\n"); + return -EINVAL; + } + + /* Parse Cell ID element -- this should yield a cell identifier "list" with 1 element. */ + + rc = gsm0808_dec_cell_id_list2(&cil, ie_cell_id->val, ie_cell_id->len); + if (rc < 0) { + LOG_RAN_A_DEC_MSG(LOGL_ERROR, "Decoding CELL IDENTIFIER gave rc=%d\n", rc); + return -EINVAL; + } + if (cil.id_list_len != 1) { + LOG_RAN_A_DEC_MSG(LOGL_ERROR, "Unable to parse element CELL IDENTIFIER, discarding message\n"); + return -EINVAL; + } + + /* Sanity check the Cell Identity */ + switch (cil.id_discr) { + case CELL_IDENT_WHOLE_GLOBAL: + case CELL_IDENT_LAI_AND_LAC: + case CELL_IDENT_LAC_AND_CI: + case CELL_IDENT_LAC: + break; + + case CELL_IDENT_CI: + case CELL_IDENT_NO_CELL: + case CELL_IDENT_BSS: + default: + LOG_RAN_A_DEC_MSG(LOGL_ERROR, "CELL IDENTIFIER does not specify a LAC, discarding message: %s\n", + gsm0808_cell_id_list_name(&cil)); + return -EINVAL; + } + + cell_id = (struct gsm0808_cell_id){ + .id_discr = cil.id_discr, + .id = cil.id_list[0], + }; + + /* Parse Layer 3 Information element */ + msg->l3h = (uint8_t*)ie_l3_info->val; + msgb_l3trim(msg, ie_l3_info->len); + + if (msgb_l3len(msg) < sizeof(struct gsm48_hdr)) { + LOG_RAN_A_DEC_MSG(LOGL_ERROR, "too short L3 info (%d), discarding message\n", msgb_l3len(msg)); + return -ENODATA; + } + + return ran_decoded(ran_dec, &ran_dec_msg); +} + +static int ran_a_decode_clear_request(struct ran_dec *ran_dec, struct msgb *msg, struct tlv_parsed *tp) +{ + struct tlv_p_entry *ie_cause = TLVP_GET(tp, GSM0808_IE_CAUSE); + struct ran_msg ran_dec_msg = { + .msg_type = RAN_MSG_CLEAR_REQUEST, + .msg_name = "BSSMAP Clear Request", + }; + + if (!ie_cause) { + LOG_RAN_A_DEC_MSG(LOGL_ERROR, "Cause code is missing, using GSM0808_CAUSE_EQUIPMENT_FAILURE\n"); + ran_dec_msg.clear_request.bssap_cause = GSM0808_CAUSE_EQUIPMENT_FAILURE; + } else { + ran_dec_msg.clear_request.bssap_cause = ie_cause->val[0]; + } + + return ran_decoded(ran_dec, &ran_dec_msg); +} + +static int ran_a_decode_clear_complete(struct ran_dec *ran_dec, struct msgb *msg, struct tlv_parsed *tp) +{ + struct ran_msg ran_dec_msg = { + .msg_type = RAN_MSG_CLEAR_COMPLETE, + .msg_name = "BSSMAP Clear Complete", + }; + return ran_decoded(ran_dec, &ran_dec_msg); +} + +static int ran_a_decode_classmark_update(struct ran_dec *ran_dec, struct msgb *msg, struct tlv_parsed *tp) +{ + struct tlv_p_entry *ie_cm2 = TLVP_GET(tp, GSM0808_IE_CLASSMARK_INFORMATION_T2); + struct tlv_p_entry *ie_cm3 = TLVP_GET(tp, GSM0808_IE_CLASSMARK_INFORMATION_T3); + struct osmo_gsm48_classmark cm = {}; + struct ran_msg ran_dec_msg = { + .msg_type = RAN_MSG_CLASSMARK_UPDATE, + .msg_name = "BSSMAP Classmark Update", + .classmark_update = { + .classmark = &cm, + }, + }; + + if (!ie_cm2) { + LOG_RAN_A_DEC_MSG(LOGL_ERROR, "mandatory Classmark Information Type 2 not present, discarding message\n"); + return -EINVAL; + } + + cm.classmark2_len = OSMO_MIN(sizeof(cm.classmark2), ie_cm2->len); + memcpy(&cm.classmark2, ie_cm2->val, cm.classmark2_len); + + if (ie_cm3) { + cm.classmark3_len = OSMO_MIN(sizeof(cm.classmark3), ie_cm3->len); + memcpy(&cm.classmark3, ie_cm3->val, cm.classmark3_len); + } + + return ran_decoded(ran_dec, &ran_dec_msg); +} + +static int ran_a_decode_cipher_mode_complete(struct ran_dec *ran_dec, struct msgb *msg, struct tlv_parsed *tp) +{ + struct tlv_p_entry *ie_chosen_encr_alg = TLVP_GET(tp, GSM0808_IE_CHOSEN_ENCR_ALG); + struct tlv_p_entry *ie_l3_msg = TLVP_GET(tp, GSM0808_IE_LAYER_3_MESSAGE_CONTENTS); + int rc; + struct ran_msg ran_dec_msg = { + .msg_type = RAN_MSG_CIPHER_MODE_COMPLETE, + .msg_name = "BSSMAP Ciphering Mode Complete", + }; + + if (ie_chosen_encr_alg) { + uint8_t ie_val = ie_chosen_encr_alg->val[0]; + /* 3GPP TS 48.008 3.2.2.44 Chosen Encryption Algorithm encodes as 1 = no encryption, 2 = A5/1, 4 = A5/3. + * Internally we handle without this weird off-by-one. */ + if (ie_val < 1 || ie_val > 8) + LOG_RAN_A_DEC_MSG(LOGL_ERROR, "Unsupported value for 3.2.2.44 Chosen Encryption Algorithm: %u\n", + ie_val); + else + ran_dec_msg.cipher_mode_complete.alg_id = ie_chosen_encr_alg->val[0]; + } + + rc = ran_decoded(ran_dec, &ran_dec_msg); + + if (ie_l3_msg) { + msg->l3h = (uint8_t*)ie_l3_msg->val; + msgb_l3trim(msg, ie_l3_msg->len); + ran_dec_msg = (struct ran_msg){ + .msg_type = RAN_MSG_DTAP, + .msg_name = "BSSMAP Ciphering Mode Complete (L3 Message Contents)", + .dtap = msg, + }; + ran_decoded(ran_dec, &ran_dec_msg); + } + + return rc; +} + +static int ran_a_decode_cipher_mode_reject(struct ran_dec *ran_dec, struct msgb *msg, struct tlv_parsed *tp) +{ + int rc; + struct ran_msg ran_dec_msg = { + .msg_type = RAN_MSG_CIPHER_MODE_REJECT, + .msg_name = "BSSMAP Ciphering Mode Reject", + }; + + rc = gsm0808_get_cipher_reject_cause(tp); + if (rc < 0) { + LOG_RAN_A_DEC_MSG(LOGL_ERROR, "failed to extract Cause\n"); + ran_dec_msg.cipher_mode_reject.bssap_cause = GSM0808_CAUSE_EQUIPMENT_FAILURE; + } else { + ran_dec_msg.cipher_mode_reject.bssap_cause = (enum gsm0808_cause)rc; + } + + return ran_decoded(ran_dec, &ran_dec_msg); +} + +enum mgcp_codecs ran_a_mgcp_codec_from_sc(const struct gsm0808_speech_codec *sc) +{ + switch (sc->type) { + case GSM0808_SCT_FR1: + return CODEC_GSM_8000_1; + break; + case GSM0808_SCT_FR2: + return CODEC_GSMEFR_8000_1; + break; + case GSM0808_SCT_FR3: + return CODEC_AMR_8000_1; + break; + case GSM0808_SCT_FR4: + return CODEC_AMRWB_16000_1; + break; + case GSM0808_SCT_FR5: + return CODEC_AMRWB_16000_1; + break; + case GSM0808_SCT_HR1: + return CODEC_GSMHR_8000_1; + break; + case GSM0808_SCT_HR3: + return CODEC_AMR_8000_1; + break; + case GSM0808_SCT_HR4: + return CODEC_AMRWB_16000_1; + break; + case GSM0808_SCT_HR6: + return CODEC_AMRWB_16000_1; + break; + default: + return CODEC_PCMU_8000_1; + break; + } +} + +static int ran_a_decode_assignment_complete(struct ran_dec *ran_dec, struct msgb *msg, struct tlv_parsed *tp) +{ + struct tlv_p_entry *ie_aoip_transp_addr = TLVP_GET(tp, GSM0808_IE_AOIP_TRASP_ADDR); + struct tlv_p_entry *ie_speech_codec = TLVP_GET(tp, GSM0808_IE_SPEECH_CODEC); + struct sockaddr_storage rtp_addr; + struct sockaddr_in *rtp_addr_in; + struct gsm0808_speech_codec sc; + int rc; + struct ran_msg ran_dec_msg = { + .msg_type = RAN_MSG_ASSIGNMENT_COMPLETE, + .msg_name = "BSSMAP Assignment Complete", + }; + + if (ie_aoip_transp_addr) { + /* Decode AoIP transport address element */ + rc = gsm0808_dec_aoip_trasp_addr(&rtp_addr, ie_aoip_transp_addr->val, ie_aoip_transp_addr->len); + if (rc < 0) { + LOG_RAN_A_DEC_MSG(LOGL_ERROR, "Unable to decode AoIP Transport Layer Address\n"); + return -EINVAL; + } + + rtp_addr_in = (struct sockaddr_in*)&rtp_addr; + + if (rtp_addr.ss_family != AF_INET) { + LOG_RAN_A_DEC_MSG(LOGL_ERROR, "Assignment Complete: IE AoIP Transport Address:" + " unsupported addressing scheme (only IPV4 supported)\n"); + return -EINVAL; + } + + if (osmo_sockaddr_str_from_sockaddr_in(&ran_dec_msg.assignment_complete.remote_rtp, rtp_addr_in)) { + LOG_RAN_A_DEC_MSG(LOGL_ERROR, "Assignment Complete: unable to decode remote RTP IP address\n"); + return -EINVAL; + } + } + + if (ie_speech_codec) { + /* Decode Speech Codec (Chosen) element */ + rc = gsm0808_dec_speech_codec(&sc, ie_speech_codec->val, ie_speech_codec->len); + if (rc < 0) { + LOG_RAN_A_DEC_MSG(LOGL_ERROR, "Assignment Complete: unable to decode IE Speech Codec (Chosen)" + " (rc=%d).\n", rc); + return -EINVAL; + } + ran_dec_msg.assignment_complete.codec_present = true; + ran_dec_msg.assignment_complete.codec = ran_a_mgcp_codec_from_sc(&sc); + } + + return ran_decoded(ran_dec, &ran_dec_msg); +} + +static int ran_a_decode_assignment_failure(struct ran_dec *ran_dec, struct msgb *msg, struct tlv_parsed *tp) +{ + struct tlv_p_entry *ie_cause = TLVP_GET(tp, GSM0808_IE_CAUSE); + struct tlv_p_entry *ie_rr_cause = TLVP_GET(tp, GSM0808_IE_RR_CAUSE); + struct tlv_p_entry *ie_speech_codec_list = TLVP_GET(tp, GSM0808_IE_SPEECH_CODEC_LIST); + struct gsm0808_speech_codec_list scl; + struct ran_msg ran_dec_msg = { + .msg_type = RAN_MSG_ASSIGNMENT_FAILURE, + .msg_name = "BSSMAP Assignment Failure", + .assignment_failure = { + .bssap_cause = GSM0808_CAUSE_EQUIPMENT_FAILURE, + .rr_cause = GSM48_RR_CAUSE_ABNORMAL_UNSPEC, + }, + }; + + if (ie_cause) + ran_dec_msg.assignment_failure.bssap_cause = ie_cause->val[0]; + if (ie_rr_cause) + ran_dec_msg.assignment_failure.rr_cause = ie_rr_cause->val[0]; + + if (ie_speech_codec_list + && gsm0808_dec_speech_codec_list(&scl, ie_speech_codec_list->val, ie_speech_codec_list->len) == 0) + ran_dec_msg.assignment_failure.scl_bss_supported = &scl; + + return ran_decoded(ran_dec, &ran_dec_msg); +} + +static int ran_a_decode_sapi_n_reject(struct ran_dec *ran_dec, struct msgb *msg, struct tlv_parsed *tp) +{ + struct tlv_p_entry *ie_cause = TLVP_GET(tp, GSM0808_IE_CAUSE); + struct tlv_p_entry *ie_dlci = TLVP_GET(tp, GSM0808_IE_DLCI); + struct ran_msg ran_dec_msg = { + .msg_type = RAN_MSG_SAPI_N_REJECT, + .msg_name = "BSSMAP SAPI-N Reject", + }; + + /* 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 */ + if (!ie_cause) { + LOG_RAN_A_DEC_MSG(LOGL_ERROR, "SAPI-N Reject: cause code IE is missing, discarding message\n"); + return -EINVAL; + } + ran_dec_msg.sapi_n_reject.bssap_cause = ie_cause->val[0]; + + if (!ie_dlci) { + LOG_RAN_A_DEC_MSG(LOGL_ERROR, "SAPI-N Reject: DLCI IE is missing, discarding message\n"); + return -EINVAL; + } + ran_dec_msg.sapi_n_reject.dlci = ie_dlci->val[0]; + + return ran_decoded(ran_dec, &ran_dec_msg); +} + +static int ran_a_decode_lcls_notification(struct ran_dec *ran_dec, const struct msgb *msg, const struct tlv_parsed *tp) +{ + const struct tlv_p_entry *ie_lcls_bss_status = TLVP_GET(tp, GSM0808_IE_LCLS_BSS_STATUS); + const struct tlv_p_entry *ie_lcls_break_req = TLVP_GET(tp, GSM0808_IE_LCLS_BREAK_REQ); + struct ran_msg ran_dec_msg; + + /* Either §3.2.2.119 LCLS-BSS-Status or §3.2.2.120 LCLS-Break-Request shall be present */ + if ((!ie_lcls_bss_status && !ie_lcls_break_req) + || (ie_lcls_bss_status && ie_lcls_break_req)) { + LOG_RAN_A_DEC(ran_dec, LOGL_ERROR, "Ignoring broken LCLS Notification message\n"); + return -EINVAL; + } + + if (ie_lcls_bss_status) { + ran_dec_msg = (struct ran_msg){ + .msg_type = RAN_MSG_LCLS_STATUS, + .msg_name = "BSSMAP LCLS Notification (LCLS Status)", + .lcls_status = { + .status = ie_lcls_bss_status->len ? + ie_lcls_bss_status->val[0] : GSM0808_LCLS_STS_NA, + }, + }; + return ran_decoded(ran_dec, &ran_dec_msg); + } + + if (ie_lcls_break_req) { + ran_dec_msg = (struct ran_msg){ + .msg_type = RAN_MSG_LCLS_BREAK_REQ, + .msg_name = "BSSMAP LCLS Notification (LCLS Break Req)", + .lcls_break_req = { + .todo = 23, + }, + }; + return ran_decoded(ran_dec, &ran_dec_msg); + } + + return -EINVAL; +} + +static int ran_a_decode_handover_required(struct ran_dec *ran_dec, const struct msgb *msg, const struct tlv_parsed *tp) +{ + const struct tlv_p_entry *ie_cause = TLVP_GET(tp, GSM0808_IE_CAUSE); + const struct tlv_p_entry *ie_cil = TLVP_GET(tp, GSM0808_IE_CELL_IDENTIFIER_LIST); + struct ran_msg ran_dec_msg = { + .msg_type = RAN_MSG_HANDOVER_REQUIRED, + .msg_name = "BSSMAP Handover Required", + }; + /* On decoding failures, dispatch an invalid RAN_MSG_HANDOVER_REQUIRED so msc_a can pass down a + * BSS_MAP_MSG_HANDOVER_REQUIRED_REJECT message. */ + + if (ie_cause) + ran_dec_msg.handover_required.cause = ie_cause->val[0]; + else + LOG_RAN_A_DEC_MSG(LOGL_ERROR, "Cause IE missing\n"); + + if (!ie_cil + || gsm0808_dec_cell_id_list2(&ran_dec_msg.handover_required.cil, ie_cil->val, ie_cil->len) <= 0) { + LOG_RAN_A_DEC_MSG(LOGL_ERROR, "No or invalid Cell Identifier List IE\n"); + ran_dec_msg.handover_required.cil = (struct gsm0808_cell_id_list2){}; + } + + return ran_decoded(ran_dec, &ran_dec_msg); +} + +static uint8_t a5_encryption_mask_from_gsm0808_chosen_enc_alg(enum gsm0808_chosen_enc_alg val) +{ + return 1 << val; +} + +static int ran_a_decode_handover_request(struct ran_dec *ran_dec, const struct msgb *msg, const struct tlv_parsed *tp) +{ + struct osmo_gsm48_classmark classmark = {}; + struct ran_msg ran_dec_msg = { + .msg_type = RAN_MSG_HANDOVER_REQUEST, + .msg_name = "BSSMAP Handover Request", + .handover_request = { + .classmark = &classmark, + }, + }; + struct ran_handover_request *r = &ran_dec_msg.handover_request; + + const struct tlv_p_entry *ie_channel_type = TLVP_GET(tp, GSM0808_IE_CHANNEL_TYPE); + const struct tlv_p_entry *ie_encryption_information = TLVP_GET(tp, GSM0808_IE_ENCRYPTION_INFORMATION); + const struct tlv_p_entry *ie_classmark1 = TLVP_GET(tp, GSM0808_IE_CLASSMARK_INFORMATION_TYPE_1); + const struct tlv_p_entry *ie_classmark2 = TLVP_GET(tp, GSM0808_IE_CLASSMARK_INFORMATION_T2); + const struct tlv_p_entry *ie_cell_id_serving = TLVP_GET(&tp[0], GSM0808_IE_CELL_IDENTIFIER); + const struct tlv_p_entry *ie_cell_id_target = TLVP_GET(&tp[1], GSM0808_IE_CELL_IDENTIFIER); + const struct tlv_p_entry *ie_cause = TLVP_GET(tp, GSM0808_IE_CAUSE); + const struct tlv_p_entry *ie_classmark3 = TLVP_GET(tp, GSM0808_IE_CLASSMARK_INFORMATION_T3); + const struct tlv_p_entry *ie_current_channel_type_1 = TLVP_GET(tp, GSM0808_IE_CURRENT_CHANNEL_TYPE_1); + const struct tlv_p_entry *ie_speech_version_used = TLVP_GET(tp, GSM0808_IE_SPEECH_VERSION); + const struct tlv_p_entry *ie_chosen_encr_alg_serving = TLVP_GET(tp, GSM0808_IE_CHOSEN_ENCR_ALG); + const struct tlv_p_entry *ie_old_bss_to_new_bss_info = TLVP_GET(tp, GSM0808_IE_OLD_BSS_TO_NEW_BSS_INFORMATION); + const struct tlv_p_entry *ie_imsi = TLVP_GET(tp, GSM0808_IE_IMSI); + const struct tlv_p_entry *ie_aoip_transp_addr = TLVP_GET(tp, GSM0808_IE_AOIP_TRASP_ADDR); + const struct tlv_p_entry *ie_codec_list_msc_preferred = TLVP_GET(tp, GSM0808_IE_SPEECH_CODEC_LIST); + const struct tlv_p_entry *ie_call_id = TLVP_GET(tp, GSM0808_IE_CALL_ID); + const struct tlv_p_entry *ie_global_call_ref = TLVP_GET(tp, GSM0808_IE_GLOBAL_CALL_REF); + + struct gsm0808_channel_type channel_type; + struct gsm0808_encrypt_info encr_info; + struct gsm0808_speech_codec_list scl; + struct geran_encr geran_encr = {}; + char imsi[OSMO_IMSI_BUF_SIZE]; + struct osmo_sockaddr_str rtp_ran_local; + + if (!ie_channel_type) { + LOG_RAN_A_DEC_MSG(LOGL_ERROR, "Mandatory IE missing: Channel Type\n"); + return -EINVAL; + } + if (gsm0808_dec_channel_type(&channel_type, ie_channel_type->val, ie_channel_type->len) <= 0) { + LOG_RAN_A_DEC_MSG(LOGL_ERROR, "Failed to decode Channel Type IE\n"); + return -EINVAL; + } + r->geran.channel_type = &channel_type; + + if (ie_encryption_information) { + int i; + if (gsm0808_dec_encrypt_info(&encr_info, ie_encryption_information->val, ie_encryption_information->len) + <= 0) { + LOG_RAN_A_DEC_MSG(LOGL_ERROR, "Failed to decode Encryption Informaiton IE\n"); + return -EINVAL; + } + + for (i = 0; i < encr_info.perm_algo_len; i++) { + r->geran.a5_encryption_mask |= + a5_encryption_mask_from_gsm0808_chosen_enc_alg(encr_info.perm_algo[i]); + } + + if (encr_info.key_len > sizeof(geran_encr.key)) { + LOG_RAN_A_DEC_MSG(LOGL_ERROR, "Failed to decode Encryption Informaiton IE:" + " encryption key is too long: %u\n", geran_encr.key_len); + return -EINVAL; + } + + if (encr_info.key_len) { + memcpy(geran_encr.key, encr_info.key, encr_info.key_len); + geran_encr.key_len = encr_info.key_len; + } + + r->geran.chosen_encryption = &geran_encr; + } + + if (!ie_classmark1 && !ie_classmark2) { + LOG_RAN_A_DEC_MSG(LOGL_ERROR, "Mandatory IE missing: either Classmark Information 1" + " or Classmark Information 2 must be included\n"); + return -EINVAL; + } + + if (ie_classmark1) { + if (ie_classmark1->len != sizeof(classmark.classmark1)) { + LOG_RAN_A_DEC_MSG(LOGL_ERROR, "Invalid size for Classmark 1: %u, expected %zu\n", + ie_classmark1->len, sizeof(classmark.classmark1)); + return -EINVAL; + } + memcpy((uint8_t*)&classmark.classmark1, ie_classmark1->val, ie_classmark1->len); + classmark.classmark1_set = true; + } + + if (ie_classmark2) { + uint8_t len = OSMO_MIN(ie_classmark2->len, sizeof(classmark.classmark2)); + memcpy((uint8_t*)&classmark.classmark2, ie_classmark2->val, len); + classmark.classmark2_len = len; + } + + if (!ie_cell_id_serving) { + LOG_RAN_A_DEC_MSG(LOGL_ERROR, "Mandatory IE missing: Cell Identifier (Serving)\n"); + return -EINVAL; + } + if (gsm0808_dec_cell_id(&r->cell_id_serving, ie_cell_id_serving->val, + ie_cell_id_serving->len) <= 0) { + LOG_RAN_A_DEC_MSG(LOGL_ERROR, "Failed to decode Cell Identifier (Serving) IE\n"); + return -EINVAL; + } + + if (!ie_cell_id_target) { + LOG_RAN_A_DEC_MSG(LOGL_ERROR, "Mandatory IE missing: Cell Identifier (Target)\n"); + return -EINVAL; + } + if (gsm0808_dec_cell_id(&r->cell_id_target, ie_cell_id_target->val, + ie_cell_id_target->len) <= 0) { + LOG_RAN_A_DEC_MSG(LOGL_ERROR, "Failed to decode Cell Identifier (Target) IE\n"); + return -EINVAL; + } + + if (ie_cause) + r->bssap_cause = ie_cause->val[0]; + + if (ie_classmark3) { + uint8_t len = OSMO_MIN(ie_classmark3->len, sizeof(classmark.classmark3)); + memcpy(classmark.classmark3, ie_classmark3->val, len); + classmark.classmark3_len = len; + } + + if (ie_current_channel_type_1) { + r->current_channel_type_1 = ie_current_channel_type_1->val[0]; + r->current_channel_type_1_present = true; + } + + if (ie_speech_version_used) { + r->speech_version_used = ie_speech_version_used->val[0]; + } + + if (ie_chosen_encr_alg_serving && ie_chosen_encr_alg_serving->len) { + geran_encr.alg_id = ie_chosen_encr_alg_serving->val[0]; + r->geran.chosen_encryption = &geran_encr; + } + + if (ie_old_bss_to_new_bss_info) { + r->old_bss_to_new_bss_info_raw = ie_old_bss_to_new_bss_info->val; + r->old_bss_to_new_bss_info_raw_len = ie_old_bss_to_new_bss_info->len; + } + + if (ie_imsi) { + gsm48_mi_to_string(imsi, sizeof(imsi), ie_imsi->val, ie_imsi->len); + r->imsi = imsi; + } + + if (ie_aoip_transp_addr) { + do { + struct sockaddr_storage rtp_addr; + if (gsm0808_dec_aoip_trasp_addr(&rtp_addr, ie_aoip_transp_addr->val, ie_aoip_transp_addr->len) < 0) { + LOG_RAN_A_DEC_MSG(LOGL_ERROR, "unable to decode AoIP transport address\n"); + break; + } + if (rtp_addr.ss_family != AF_INET) { + LOG_RAN_A_DEC_MSG(LOGL_ERROR, "IE AoIP Transport Address:" + " unsupported addressing scheme (only IPV4 supported)\n"); + break; + } + if (osmo_sockaddr_str_from_sockaddr_in(&rtp_ran_local, (struct sockaddr_in*)&rtp_addr)) { + LOG_RAN_A_DEC_MSG(LOGL_ERROR, "unable to decode remote RTP IP address\n"); + break; + } + r->rtp_ran_local = &rtp_ran_local; + } while(0); + } + + if (ie_codec_list_msc_preferred + && gsm0808_dec_speech_codec_list(&scl, ie_codec_list_msc_preferred->val, + ie_codec_list_msc_preferred->len) == 0) + r->codec_list_msc_preferred = &scl; + + if (ie_call_id && ie_call_id->len == 4) { + r->call_id = osmo_load32le(ie_call_id->val); + r->call_id_present = true; + } + + if (ie_global_call_ref) { + r->global_call_reference = ie_global_call_ref->val; + r->global_call_reference_len = ie_global_call_ref->len; + } + + return ran_decoded(ran_dec, &ran_dec_msg); +} + +static int ran_a_decode_handover_request_ack(struct ran_dec *ran_dec, const struct msgb *msg, const struct tlv_parsed *tp) +{ + struct ran_msg ran_dec_msg = { + .msg_type = RAN_MSG_HANDOVER_REQUEST_ACK, + .msg_name = "BSSMAP Handover Request Acknowledge", + }; + const struct tlv_p_entry *ie_l3_info = TLVP_GET(tp, GSM0808_IE_LAYER_3_INFORMATION); + const struct tlv_p_entry *ie_aoip_transp_addr = TLVP_GET(tp, GSM0808_IE_AOIP_TRASP_ADDR); + const struct tlv_p_entry *ie_speech_codec = TLVP_GET(tp, GSM0808_IE_SPEECH_CODEC); + const struct tlv_p_entry *ie_chosen_channel = TLVP_GET(tp, GSM0808_IE_CHOSEN_CHANNEL); + const struct tlv_p_entry *ie_chosen_encr_alg = TLVP_GET(tp, GSM0808_IE_CHOSEN_ENCR_ALG); + const struct tlv_p_entry *ie_chosen_speech_version = TLVP_GET(tp, GSM0808_IE_SPEECH_VERSION); + + /* On missing mandatory IEs, dispatch an invalid RAN_MSG_HANDOVER_REQUEST_ACK so msc_a can act on the failure. */ + + if (ie_l3_info) { + ran_dec_msg.handover_request_ack.rr_ho_command = ie_l3_info->val; + ran_dec_msg.handover_request_ack.rr_ho_command_len = ie_l3_info->len; + } + + if (ie_chosen_channel) { + ran_dec_msg.handover_request_ack.chosen_channel_present = true; + ran_dec_msg.handover_request_ack.chosen_channel = *ie_chosen_channel->val; + } + + if (ie_chosen_encr_alg) { + ran_dec_msg.handover_request_ack.chosen_encr_alg = *ie_chosen_encr_alg->val; + if (ran_dec_msg.handover_request_ack.chosen_encr_alg < 1 + || ran_dec_msg.handover_request_ack.chosen_encr_alg > 8) { + LOG_RAN_A_DEC_MSG(LOGL_ERROR, "invalid Chosen Encryption Algorithm: %u\n", + ran_dec_msg.handover_request_ack.chosen_encr_alg); + } + } + + if (ie_chosen_speech_version) { + struct gsm0808_speech_codec sc; + ran_dec_msg.handover_request_ack.chosen_speech_version = ie_chosen_speech_version->val[0]; + + /* the codec may be extrapolated from this Speech Version or below from Speech Codec */ + gsm0808_speech_codec_from_chan_type(&sc, ran_dec_msg.handover_request_ack.chosen_speech_version); + ran_dec_msg.handover_request_ack.codec_present = true; + ran_dec_msg.handover_request_ack.codec = ran_a_mgcp_codec_from_sc(&sc); + } + + if (ie_aoip_transp_addr) { + do { + struct sockaddr_storage rtp_addr; + if (gsm0808_dec_aoip_trasp_addr(&rtp_addr, ie_aoip_transp_addr->val, ie_aoip_transp_addr->len) < 0) { + LOG_RAN_A_DEC_MSG(LOGL_ERROR, "unable to decode AoIP transport address\n"); + break; + } + if (rtp_addr.ss_family != AF_INET) { + LOG_RAN_A_DEC_MSG(LOGL_ERROR, "IE AoIP Transport Address:" + " unsupported addressing scheme (only IPV4 supported)\n"); + break; + } + if (osmo_sockaddr_str_from_sockaddr_in(&ran_dec_msg.handover_request_ack.remote_rtp, + (struct sockaddr_in*)&rtp_addr)) { + LOG_RAN_A_DEC_MSG(LOGL_ERROR, "unable to decode remote RTP IP address\n"); + ran_dec_msg.handover_request_ack.remote_rtp = (struct osmo_sockaddr_str){}; + break; + } + } while(0); + } + + if (ie_speech_codec) { + struct gsm0808_speech_codec sc; + if (gsm0808_dec_speech_codec(&sc, ie_speech_codec->val, ie_speech_codec->len) < 0) + LOG_RAN_A_DEC_MSG(LOGL_ERROR, "unable to decode IE Speech Codec (Chosen)\n"); + else { + /* the codec may be extrapolated from above Speech Version or from this Speech Codec */ + ran_dec_msg.handover_request_ack.codec_present = true; + ran_dec_msg.handover_request_ack.codec = ran_a_mgcp_codec_from_sc(&sc); + } + } + + return ran_decoded(ran_dec, &ran_dec_msg); +} + +static int ran_a_decode_handover_detect(struct ran_dec *ran_dec, const struct msgb *msg, const struct tlv_parsed *tp) +{ + struct ran_msg ran_dec_msg = { + .msg_type = RAN_MSG_HANDOVER_DETECT, + .msg_name = "BSSMAP Handover Detect", + }; + + return ran_decoded(ran_dec, &ran_dec_msg); +} + +static int ran_a_decode_handover_succeeded(struct ran_dec *ran_dec, const struct msgb *msg, const struct tlv_parsed *tp) +{ + struct ran_msg ran_dec_msg = { + .msg_type = RAN_MSG_HANDOVER_SUCCEEDED, + .msg_name = "BSSMAP Handover Succeeded", + }; + + return ran_decoded(ran_dec, &ran_dec_msg); +} + +static int ran_a_decode_handover_complete(struct ran_dec *ran_dec, const struct msgb *msg, const struct tlv_parsed *tp) +{ + struct ran_msg ran_dec_msg = { + .msg_type = RAN_MSG_HANDOVER_COMPLETE, + .msg_name = "BSSMAP Handover Complete", + }; + + return ran_decoded(ran_dec, &ran_dec_msg); +} + +static int ran_a_decode_handover_failure(struct ran_dec *ran_dec, const struct msgb *msg, const struct tlv_parsed *tp) +{ + struct ran_msg ran_dec_msg = { + .msg_type = RAN_MSG_HANDOVER_FAILURE, + .msg_name = "BSSMAP Handover Failure", + }; + + return ran_decoded(ran_dec, &ran_dec_msg); +} + +static int ran_a_decode_bssmap(struct ran_dec *ran_dec, struct msgb *bssmap) +{ + struct tlv_parsed tp[2]; + int rc; + struct bssmap_header *h = msgb_l2(bssmap); + uint8_t msg_type; + bssmap->l3h = bssmap->l2h + sizeof(*h); + + if (msgb_l3len(bssmap) < 1) { + LOG_RAN_A_DEC(ran_dec, LOGL_ERROR, "No data received, discarding message\n"); + return -1; + } + + if (msgb_l3len(bssmap) < h->length) { + LOG_RAN_A_DEC(ran_dec, LOGL_ERROR, "BSSMAP data truncated, discarding message\n"); + return -1; + } + + if (msgb_l3len(bssmap) > h->length) { + LOG_RAN_A_DEC(ran_dec, LOGL_NOTICE, "There are %u extra bytes after the BSSMAP data, truncating\n", + msgb_l3len(bssmap) - h->length); + msgb_l3trim(bssmap, h->length); + } + + /* h->type == BSSAP_MSG_BSS_MANAGEMENT; h->length is the data length, + * which starts with the MAP msg_type, followed by IEs. */ + msg_type = bssmap->l3h[0]; + rc = osmo_bssap_tlv_parse2(tp, ARRAY_SIZE(tp), bssmap->l3h + 1, h->length - 1); + if (rc < 0) { + LOG_RAN_A_DEC(ran_dec, LOGL_ERROR, "Failed parsing TLV, discarding message\n"); + return -EINVAL; + } + + LOG_RAN_A_DEC(ran_dec, LOGL_DEBUG, "Rx BSSMAP DT1 %s\n", gsm0808_bssmap_name(msg_type)); + + switch (msg_type) { + case BSS_MAP_MSG_COMPLETE_LAYER_3: + return ran_a_decode_l3_compl(ran_dec, bssmap, tp); + case BSS_MAP_MSG_CLEAR_RQST: + return ran_a_decode_clear_request(ran_dec, bssmap, tp); + case BSS_MAP_MSG_CLEAR_COMPLETE: + return ran_a_decode_clear_complete(ran_dec, bssmap, tp); + case BSS_MAP_MSG_CLASSMARK_UPDATE: + return ran_a_decode_classmark_update(ran_dec, bssmap, tp); + case BSS_MAP_MSG_CIPHER_MODE_COMPLETE: + return ran_a_decode_cipher_mode_complete(ran_dec, bssmap, tp); + case BSS_MAP_MSG_CIPHER_MODE_REJECT: + return ran_a_decode_cipher_mode_reject(ran_dec, bssmap, tp); + case BSS_MAP_MSG_ASSIGMENT_COMPLETE: + rc = ran_a_decode_assignment_complete(ran_dec, bssmap, tp); + if (rc < 0) { + struct ran_msg ran_dec_msg = { + .msg_type = RAN_MSG_ASSIGNMENT_FAILURE, + .msg_name = "BSSMAP Assignment Complete but failed to decode", + .clear_request = { + .bssap_cause = GSM0808_CAUSE_EQUIPMENT_FAILURE, + }, + }; + ran_decoded(ran_dec, &ran_dec_msg); + } + return rc; + case BSS_MAP_MSG_ASSIGMENT_FAILURE: + return ran_a_decode_assignment_failure(ran_dec, bssmap, tp); + case BSS_MAP_MSG_SAPI_N_REJECT: + return ran_a_decode_sapi_n_reject(ran_dec, bssmap, tp); + case BSS_MAP_MSG_LCLS_NOTIFICATION: + return ran_a_decode_lcls_notification(ran_dec, bssmap, tp); + + /* From current RAN peer, the Handover origin: */ + case BSS_MAP_MSG_HANDOVER_REQUIRED: + return ran_a_decode_handover_required(ran_dec, bssmap, tp); + + /* From current MSC to remote handover target MSC */ + case BSS_MAP_MSG_HANDOVER_RQST: + return ran_a_decode_handover_request(ran_dec, bssmap, tp); + + /* From potential new RAN peer, the Handover target: */ + case BSS_MAP_MSG_HANDOVER_RQST_ACKNOWLEDGE: + return ran_a_decode_handover_request_ack(ran_dec, bssmap, tp); + case BSS_MAP_MSG_HANDOVER_DETECT: + return ran_a_decode_handover_detect(ran_dec, bssmap, tp); + case BSS_MAP_MSG_HANDOVER_SUCCEEDED: + return ran_a_decode_handover_succeeded(ran_dec, bssmap, tp); + case BSS_MAP_MSG_HANDOVER_COMPLETE: + return ran_a_decode_handover_complete(ran_dec, bssmap, tp); + + /* From any Handover peer: */ + case BSS_MAP_MSG_HANDOVER_FAILURE: + return ran_a_decode_handover_failure(ran_dec, bssmap, tp); + + default: + LOG_RAN_A_DEC(ran_dec, LOGL_ERROR, "Unimplemented msg type: %s\n", gsm0808_bssmap_name(msg_type)); + return -EINVAL; + } + + return -EINVAL; +} + +static int ran_a_decode_l3(struct ran_dec *ran_dec, struct msgb *l3) +{ + struct dtap_header *dtap = msgb_l2(l3); + struct ran_msg ran_dec_msg = { + .msg_type = RAN_MSG_DTAP, + .msg_name = "BSSAP DTAP", + .dtap = l3, + }; + l3->l3h = l3->l2h + sizeof(struct dtap_header); + OMSC_LINKID_CB(l3) = dtap->link_id; + return ran_decoded(ran_dec, &ran_dec_msg); +} + +int ran_a_decode_l2(struct ran_dec *ran_dec, struct msgb *bssap) +{ + uint8_t bssap_type; + OSMO_ASSERT(bssap); + + if (!msgb_l2(bssap) || !msgb_l2len(bssap)) { + LOG_RAN_A_DEC(ran_dec, LOGL_ERROR, "Cannot decode L2, msg->l2h is unset / empty: %s\n", + msgb_hexdump(bssap)); + return -EINVAL; + } + + if (msgb_l2len(bssap) < sizeof(struct bssmap_header)) { + LOG_RAN_A_DEC(ran_dec, LOGL_ERROR, "The header is too short -- discarding message\n"); + return -EINVAL; + } + + bssap_type = bssap->l2h[0]; + switch (bssap_type) { + case BSSAP_MSG_BSS_MANAGEMENT: + return ran_a_decode_bssmap(ran_dec, bssap); + case BSSAP_MSG_DTAP: + return ran_a_decode_l3(ran_dec, bssap); + default: + LOG_RAN_A_DEC(ran_dec, LOGL_ERROR, "Unimplemented BSSAP msg type: %s\n", gsm0808_bssap_name(bssap_type)); + return -EINVAL; + } +} + +static struct msgb *ran_a_wrap_dtap(struct msgb *dtap) +{ + struct msgb *an_apdu; + dtap->l3h = dtap->data; + an_apdu = gsm0808_create_dtap(dtap, OMSC_LINKID_CB(dtap)); + an_apdu->l2h = an_apdu->data; + msgb_free(dtap); + return an_apdu; +} + +static int ran_a_channel_type_to_speech_codec_list(struct gsm0808_speech_codec_list *scl, const struct gsm0808_channel_type *ct) +{ + unsigned int i; + int rc; + + memset(scl, 0, sizeof(*scl)); + for (i = 0; i < ct->perm_spch_len; i++) { + rc = gsm0808_speech_codec_from_chan_type(&scl->codec[i], ct->perm_spch[i]); + if (rc != 0) + return -EINVAL; + } + scl->len = i; + + return 0; +} + +/* Compose a BSSAP Assignment Command. + * Passing an RTP address is optional. + * The msub is passed merely for error logging. */ +static struct msgb *ran_a_make_assignment_command(struct osmo_fsm_inst *log_fi, + const struct ran_assignment_command *ac) +{ + struct gsm0808_speech_codec_list scl; + struct gsm0808_speech_codec_list *use_scl = NULL; + struct sockaddr_storage rtp_addr; + struct sockaddr_storage *use_rtp_addr = NULL; + int rc; + + if (!ac->channel_type) { + LOG_RAN_A_ENC(log_fi, LOGL_ERROR, "Assignment Command: missing Channel Type\n"); + return NULL; + } + + if (ac->channel_type->ch_indctr == GSM0808_CHAN_SPEECH) { + rc = ran_a_channel_type_to_speech_codec_list(&scl, ac->channel_type); + if (rc < 0) { + LOG_RAN_A_ENC(log_fi, LOGL_ERROR, "Assignment Command: Cannot translate Channel Type to Speech Codec List\n"); + return NULL; + } + use_scl = &scl; + + /* Package RTP-Address data */ + if (osmo_sockaddr_str_is_set(ac->cn_rtp)) { + struct sockaddr_in rtp_addr_in; + + memset(&rtp_addr_in, 0, sizeof(rtp_addr_in)); + rtp_addr_in.sin_family = AF_INET; + rtp_addr_in.sin_port = osmo_htons(ac->cn_rtp->port), + rtp_addr_in.sin_addr.s_addr = inet_addr(ac->cn_rtp->ip); + + if (rtp_addr_in.sin_addr.s_addr == INADDR_NONE) { + LOG_RAN_A_ENC(log_fi, LOGL_ERROR, "Assignment Command: Invalid RTP-Address\n"); + return NULL; + } + if (rtp_addr_in.sin_port == 0) { + LOG_RAN_A_ENC(log_fi, LOGL_ERROR, "Assignment Command: Invalid RTP-Port\n"); + return NULL; + } + + memset(&rtp_addr, 0, sizeof(rtp_addr)); + memcpy(&rtp_addr, &rtp_addr_in, sizeof(rtp_addr_in)); + + use_rtp_addr = &rtp_addr; + } + } + + return gsm0808_create_ass(ac->channel_type, NULL, use_rtp_addr, use_scl, NULL); +} + +/* For an A5/N number a5_n set dst to the matching GSM0808_ALG_ID_A5_<n>. */ +static int a5_n_to_gsm0808_chosen_enc_alg(uint8_t *dst, int a5_n) +{ + switch (a5_n) { + case 0: + *dst = GSM0808_ALG_ID_A5_0; + return 0; + case 1: + *dst = GSM0808_ALG_ID_A5_1; + return 0; + case 2: + *dst = GSM0808_ALG_ID_A5_2; + return 0; + case 3: + *dst = GSM0808_ALG_ID_A5_3; + return 0; + default: + return -ENOTSUP; + } +} + +static int make_encrypt_info_perm_algo(struct osmo_fsm_inst *fi, struct gsm0808_encrypt_info *ei, + uint8_t a5_encryption_mask, const struct osmo_gsm48_classmark *cm) +{ + int i; + int j = 0; + for (i = 0; i < 8; i++) { + int supported; + + /* A5/n permitted by osmo-msc.cfg? */ + if (!(a5_encryption_mask & (1 << i))) + continue; + + /* A5/n supported by MS? */ + supported = osmo_gsm48_classmark_supports_a5(cm, i); + if (supported != 1) + continue; + + if (a5_n_to_gsm0808_chosen_enc_alg(&ei->perm_algo[j], i)) { + LOG_RAN_A_ENC(fi, LOGL_ERROR, "Not supported: A5/%d algorithm\n", i); + return -1; + } + j++; + ei->perm_algo_len = j; + } + return 0; +} + +/* For ran_a_make_cipher_mode_command(), for + * memcpy(ei.key, cm->vec->kc, sizeof(cm->vec->kc)); + */ +osmo_static_assert(sizeof(((struct gsm0808_encrypt_info*)0)->key) >= sizeof(((struct osmo_auth_vector*)0)->kc), + gsm0808_encrypt_info_key_fits_osmo_auth_vec_kc); +static struct msgb *ran_a_make_cipher_mode_command(struct osmo_fsm_inst *fi, const struct ran_cipher_mode_command *cm) +{ + struct gsm0808_encrypt_info ei = {}; + char buf[16 * 2 + 1]; + const uint8_t cipher_response_mode = 1; + + if (make_encrypt_info_perm_algo(fi, &ei, cm->geran.a5_encryption_mask, cm->classmark)) + return NULL; + + if (ei.perm_algo_len == 0) { + LOG_RAN_A_ENC(fi, LOGL_ERROR, "cannot start ciphering, no intersection between MSC-configured" + " and MS-supported A5 algorithms. MSC: 0x%02x MS: %s\n", + cm->geran.a5_encryption_mask, osmo_gsm48_classmark_a5_name(cm->classmark)); + return NULL; + } + + /* In case of UMTS AKA, the Kc for ciphering must be derived from the 3G auth + * tokens. vec->kc was calculated from the GSM algorithm and is not + * necessarily a match for the UMTS AKA tokens. */ + if (cm->geran.umts_aka) + osmo_auth_c3(ei.key, cm->vec->ck, cm->vec->ik); + else + memcpy(ei.key, cm->vec->kc, sizeof(cm->vec->kc)); + ei.key_len = sizeof(cm->vec->kc); + + /* Store chosen GERAN key where the caller asked it to be stored. + * alg_id remains unknown until we receive a Cipher Mode Complete from the BSC */ + if (cm->geran.chosen_key) { + if (ei.key_len > sizeof(cm->geran.chosen_key->key)) { + LOG_RAN_A_ENC(fi, LOGL_ERROR, "Chosen key is larger than I can store\n"); + return NULL; + } + memcpy(cm->geran.chosen_key->key, ei.key, ei.key_len); + cm->geran.chosen_key->key_len = ei.key_len; + } + + LOG_RAN_A_ENC(fi, LOGL_DEBUG, "Tx BSSMAP CIPHER MODE COMMAND to BSC, %u ciphers (%s) key %s\n", + ei.perm_algo_len, osmo_hexdump_nospc(ei.perm_algo, ei.perm_algo_len), + osmo_hexdump_buf(buf, sizeof(buf), ei.key, ei.key_len, NULL, false)); + return gsm0808_create_cipher(&ei, cm->geran.retrieve_imeisv ? &cipher_response_mode : NULL); +} + +struct msgb *ran_a_make_handover_request(struct osmo_fsm_inst *log_fi, const struct ran_handover_request *n) +{ + struct sockaddr_storage ss; + struct gsm0808_handover_request r = { + .cell_identifier_serving = n->cell_id_serving, + .cell_identifier_target = n->cell_id_target, + .cause = n->bssap_cause, + .current_channel_type_1_present = n->current_channel_type_1_present, + .current_channel_type_1 = n->current_channel_type_1, + + .speech_version_used = n->speech_version_used, + + .chosen_encryption_algorithm_serving = n->geran.chosen_encryption->alg_id, + + .old_bss_to_new_bss_info_raw = n->old_bss_to_new_bss_info_raw, + .old_bss_to_new_bss_info_raw_len = n->old_bss_to_new_bss_info_raw_len, + + .imsi = n->imsi, + .codec_list_msc_preferred = n->codec_list_msc_preferred, + .call_id = n->call_id, + .global_call_reference = n->global_call_reference, + .global_call_reference_len = n->global_call_reference_len, + }; + + if (!n->geran.channel_type) { + LOG_RAN_A_ENC(log_fi, LOGL_ERROR, "Channel Type required for encoding Handover Request in BSSAP\n"); + return NULL; + } + r.channel_type = *n->geran.channel_type; + + /* Encryption Information */ + make_encrypt_info_perm_algo(log_fi, &r.encryption_information, n->geran.a5_encryption_mask, n->classmark); + if (n->geran.chosen_encryption && n->geran.chosen_encryption->key_len) { + if (n->geran.chosen_encryption->key_len > sizeof(r.encryption_information.key)) { + LOG_RAN_A_ENC(log_fi, LOGL_ERROR, "Handover Request: invalid chosen encryption key size %u\n", + n->geran.chosen_encryption->key_len); + return NULL; + } + memcpy(r.encryption_information.key, + n->geran.chosen_encryption->key, n->geran.chosen_encryption->key_len); + r.encryption_information.key_len = n->geran.chosen_encryption->key_len; + } + + if (n->classmark) + r.classmark_information = *n->classmark; + + if (osmo_sockaddr_str_is_set(n->rtp_ran_local)) { + if (osmo_sockaddr_str_to_sockaddr(n->rtp_ran_local, &ss)) { + LOG_RAN_A_ENC(log_fi, LOGL_ERROR, + "Handover Request: invalid AoIP Transport Layer address/port: " + OSMO_SOCKADDR_STR_FMT "\n", OSMO_SOCKADDR_STR_FMT_ARGS(n->rtp_ran_local)); + return NULL; + } + r.aoip_transport_layer = &ss; + } + + return gsm0808_create_handover_request(&r); +} + +static struct msgb *ran_a_make_handover_request_ack(struct osmo_fsm_inst *caller_fi, const struct ran_handover_request_ack *r) +{ + struct sockaddr_storage ss; + struct gsm0808_handover_request_ack params = { + .l3_info = r->rr_ho_command, + .l3_info_len = r->rr_ho_command_len, + .chosen_channel_present = r->chosen_channel_present, + .chosen_channel = r->chosen_channel, + .chosen_encr_alg = r->chosen_encr_alg, + .chosen_speech_version = r->chosen_speech_version, + }; + + if (osmo_sockaddr_str_is_set(&r->remote_rtp)) { + osmo_sockaddr_str_to_sockaddr(&r->remote_rtp, &ss); + params.aoip_transport_layer = &ss; + } + + return gsm0808_create_handover_request_ack2(¶ms); +} + +struct msgb *ran_a_make_handover_command(struct osmo_fsm_inst *log_fi, const struct ran_handover_command *n) +{ + struct gsm0808_handover_command c = { + .l3_info = n->rr_ho_command, + .l3_info_len = n->rr_ho_command_len, + }; + + return gsm0808_create_handover_command(&c); +} + +struct msgb *ran_a_make_handover_failure(struct osmo_fsm_inst *log_fi, const struct ran_msg *msg) +{ + struct gsm0808_handover_failure params = { + .cause = msg->handover_failure.cause, + }; + return gsm0808_create_handover_failure(¶ms); +} + +static struct msgb *_ran_a_encode(struct osmo_fsm_inst *caller_fi, const struct ran_msg *ran_enc_msg) +{ + + LOG_RAN_A_ENC(caller_fi, LOGL_DEBUG, "%s\n", ran_msg_type_name(ran_enc_msg->msg_type)); + + switch (ran_enc_msg->msg_type) { + + case RAN_MSG_DTAP: + return ran_a_wrap_dtap(ran_enc_msg->dtap); + + case RAN_MSG_CLASSMARK_REQUEST: + return gsm0808_create_classmark_request(); + + case RAN_MSG_CLEAR_COMMAND: + return gsm0808_create_clear_command2(ran_enc_msg->clear_command.gsm0808_cause, + ran_enc_msg->clear_command.csfb_ind); + + case RAN_MSG_ASSIGNMENT_COMMAND: + return ran_a_make_assignment_command(caller_fi, &ran_enc_msg->assignment_command); + + case RAN_MSG_CIPHER_MODE_COMMAND: + return ran_a_make_cipher_mode_command(caller_fi, &ran_enc_msg->cipher_mode_command); + + case RAN_MSG_HANDOVER_REQUIRED_REJECT: + return gsm0808_create_handover_required_reject(&ran_enc_msg->handover_required_reject); + + case RAN_MSG_HANDOVER_REQUEST: + return ran_a_make_handover_request(caller_fi, &ran_enc_msg->handover_request); + + case RAN_MSG_HANDOVER_REQUEST_ACK: + return ran_a_make_handover_request_ack(caller_fi, &ran_enc_msg->handover_request_ack); + + case RAN_MSG_HANDOVER_COMMAND: + return ran_a_make_handover_command(caller_fi, &ran_enc_msg->handover_command); + + case RAN_MSG_HANDOVER_SUCCEEDED: + return gsm0808_create_handover_succeeded(); + + case RAN_MSG_HANDOVER_FAILURE: + return ran_a_make_handover_failure(caller_fi, ran_enc_msg); + + default: + LOG_RAN_A_ENC(caller_fi, LOGL_ERROR, "Unimplemented RAN-encode message type: %s\n", + ran_msg_type_name(ran_enc_msg->msg_type)); + return NULL; + } +} + +struct msgb *ran_a_encode(struct osmo_fsm_inst *caller_fi, const struct ran_msg *ran_enc_msg) +{ + struct msgb *msg = _ran_a_encode(caller_fi, ran_enc_msg); + + if (!msg) + return NULL; + + msg->l2h = msg->data; + + /* some consistency checks to ensure we don't send invalid length */ + switch (msg->l2h[0]) { + case BSSAP_MSG_DTAP: + OSMO_ASSERT(msgb_l2len(msg) == msg->l2h[2] + 3); + break; + case BSSAP_MSG_BSS_MANAGEMENT: + OSMO_ASSERT(msgb_l2len(msg) == msg->l2h[1] + 2); + break; + default: + break; + } + + return msg; +} + +/* Return 1 for a RESET, 2 for a RESET ACK message, 0 otherwise */ +enum reset_msg_type bssmap_is_reset_msg(const struct sccp_ran_inst *sri, const struct msgb *l2) +{ + struct bssmap_header *bs = (struct bssmap_header *)msgb_l2(l2); + + if (!bs + || msgb_l2len(l2) < (sizeof(*bs) + 1) + || bs->type != BSSAP_MSG_BSS_MANAGEMENT) + return SCCP_RAN_MSG_NON_RESET; + + switch (l2->l2h[sizeof(*bs)]) { + case BSS_MAP_MSG_RESET: + return SCCP_RAN_MSG_RESET; + case BSS_MAP_MSG_RESET_ACKNOWLEDGE: + return SCCP_RAN_MSG_RESET_ACK; + default: + return SCCP_RAN_MSG_NON_RESET; + } +} + +struct msgb *bssmap_make_reset_msg(const struct sccp_ran_inst *sri, enum reset_msg_type type) +{ + switch (type) { + case SCCP_RAN_MSG_RESET: + return gsm0808_create_reset(); + case SCCP_RAN_MSG_RESET_ACK: + return gsm0808_create_reset_ack(); + default: + return NULL; + } +} + +struct msgb *bssmap_make_paging_msg(const struct sccp_ran_inst *sri, const struct gsm0808_cell_id *page_cell_id, + const char *imsi, uint32_t tmsi, enum paging_cause cause) +{ + struct gsm0808_cell_id_list2 cil; + gsm0808_cell_id_to_list(&cil, page_cell_id); + return gsm0808_create_paging2(imsi, tmsi == GSM_RESERVED_TMSI ? NULL : &tmsi, &cil, NULL); +} + +const char *bssmap_msg_name(const struct sccp_ran_inst *sri, const struct msgb *l2) +{ + struct bssmap_header *bs; + + if (!l2->l2h) + return "?"; + + bs = (struct bssmap_header *)msgb_l2(l2); + switch (bs->type) { + case BSSAP_MSG_BSS_MANAGEMENT: + return gsm0808_bssmap_name(l2->l2h[0]); + case BSSAP_MSG_DTAP: + return "DTAP"; + default: + return "?"; + } +} |