Osmocom Mobile Switching Centre
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/* API to forward upcoming NAS events, e.g. from BSSAP and RANAP, to be handled by MSC-A or MSC-I. */
* (C) 2019 by sysmocom s.f.m.c. GmbH <info@sysmocom.de>
* Author: Neels Hofmeyr <neels@hofmeyr.de>
* 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
* 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/>.
#pragma once
#include <osmocom/core/utils.h>
#include <osmocom/core/fsm.h>
#include <osmocom/core/sockaddr_str.h>
#include <osmocom/gsm/protocol/gsm_08_08.h>
#include <osmocom/mgcp_client/mgcp_client.h>
#include <osmocom/msc/msc_common.h>
struct msgb;
struct osmo_fsm_inst;
#define LOG_RAN_DEC(NAS_DEC, subsys, level, fmt, args...) \
LOGPFSMSL((NAS_DEC)? (NAS_DEC)->caller_fi : NULL, subsys, level, "RAN decode: " fmt, ## args)
#define LOG_RAN_ENC(FI, subsys, level, fmt, args...) \
LOGPFSMSL(FI, subsys, level, "RAN encode: " fmt, ## args)
/* These message types are named after the BSSAP procedures in nas_a.h; most are also used for RANAP procedures of
* similar meaning in nas_iu.h. */
enum ran_msg_type {
extern const struct value_string ran_msg_type_names[];
static inline const char *ran_msg_type_name(enum ran_msg_type val)
{ return get_value_string(ran_msg_type_names, val); }
struct ran_clear_command {
enum gsm0808_cause gsm0808_cause;
bool csfb_ind;
struct ran_assignment_command {
const struct osmo_sockaddr_str *cn_rtp;
const struct gsm0808_channel_type *channel_type;
enum nsap_addr_enc rab_assign_addr_enc;
bool osmux_present;
uint8_t osmux_cid;
bool call_id_present;
uint32_t call_id;
struct osmo_lcls *lcls;
struct ran_cipher_mode_command {
const struct osmo_auth_vector *vec;
const struct osmo_gsm48_classmark *classmark;
struct {
bool umts_aka;
bool retrieve_imeisv;
uint8_t a5_encryption_mask;
/* out-argument to return the key to the caller, pass NULL if not needed. */
struct geran_encr *chosen_key;
} geran;
struct {
uint8_t uea_encryption_mask;
} utran;
struct ran_handover_request {
const char *imsi;
const struct osmo_gsm48_classmark *classmark;
/* A Handover Request on GERAN-A sends separate IEs for
* - permitted algorithms, here composed from the a5_encryption_mask,
* - the key, here taken from chosen_encryption->key iff chosen_encryption is present,
* - the actually chosen algorithm ("Serving"), here taken from chosen_encryption->alg_id.
struct {
struct gsm0808_channel_type *channel_type;
uint8_t a5_encryption_mask;
/*! chosen_encryption->alg_id is in encoded format:
* alg_id == 1 means A5/0 i.e. no encryption, alg_id == 4 means A5/3.
* alg_id == 0 means no such IE was present. */
struct geran_encr *chosen_encryption;
} geran;
struct gsm0808_cell_id cell_id_serving;
struct gsm0808_cell_id cell_id_target;
enum gsm0808_cause bssap_cause;
bool current_channel_type_1_present;
uint8_t current_channel_type_1;
enum gsm0808_permitted_speech speech_version_used;
const uint8_t *old_bss_to_new_bss_info_raw;
uint8_t old_bss_to_new_bss_info_raw_len;
struct osmo_sockaddr_str *rtp_ran_local;
struct gsm0808_speech_codec_list *codec_list_msc_preferred;
bool call_id_present;
uint32_t call_id;
const uint8_t *global_call_reference;
uint8_t global_call_reference_len;
struct ran_handover_request_ack {
const uint8_t *rr_ho_command;
uint8_t rr_ho_command_len;
bool chosen_channel_present;
uint8_t chosen_channel;
/*! chosen_encr_alg is in encoded format:
* chosen_encr_alg == 1 means A5/0 i.e. no encryption, chosen_encr_alg == 4 means A5/3.
* chosen_encr_alg == 0 means no such IE was present. */
uint8_t chosen_encr_alg;
/* chosen_speech_version == 0 means "not present" */
enum gsm0808_permitted_speech chosen_speech_version;
struct osmo_sockaddr_str remote_rtp;
bool codec_present;
enum mgcp_codecs codec;
struct ran_handover_command {
const uint8_t *rr_ho_command;
uint8_t rr_ho_command_len;
const uint8_t *new_bss_to_old_bss_info_raw;
uint8_t new_bss_to_old_bss_info_raw_len;
struct ran_handover_required {
uint16_t cause;
struct gsm0808_cell_id_list2 cil;
bool current_channel_type_1_present;
/*! See gsm0808_chosen_channel() */
uint8_t current_channel_type_1;
enum gsm0808_permitted_speech speech_version_used;
uint8_t *old_bss_to_new_bss_info_raw;
size_t old_bss_to_new_bss_info_raw_len;
struct ran_msg {
enum ran_msg_type msg_type;
/* Since different RAN implementations feed these messages, they should place here an implementation specific
* string constant to name the actual message (e.g. "BSSMAP Assignment Complete" vs. "RANAP RAB Assignment
* Response") */
const char *msg_name;
union {
struct {
const struct gsm0808_cell_id *cell_id;
const struct gsm0808_speech_codec_list *codec_list_bss_supported;
struct msgb *msg;
} compl_l3;
struct msgb *dtap;
struct {
enum gsm0808_cause bssap_cause;
} clear_request;
struct ran_clear_command clear_command;
struct {
const struct osmo_gsm48_classmark *classmark;
} classmark_update;
struct ran_cipher_mode_command cipher_mode_command;
struct {
/*! alg_id is in encoded format:
* alg_id == 1 means A5/0 i.e. no encryption, alg_id == 4 means A5/3.
* alg_id == 0 means no such IE was present. */
uint8_t alg_id;
/*! utran integrity protection. 0..15 */
int16_t utran_integrity;
/*! utran_integrity is in encoded format:
* utran_integrity == -1 means no such IE was present
* utran_integrity == 0 means no encryption. */
int16_t utran_encryption;
const char *imeisv;
const struct tlv_p_entry *l3_msg;
} cipher_mode_complete;
struct {
enum gsm0808_cause bssap_cause;
} cipher_mode_reject;
struct {
const char *imsi;
bool last_eutran_plmn_present;
struct osmo_plmn_id last_eutran_plmn;
} common_id;
struct {
enum gsm48_reject_value cause;
} cm_service_reject;
struct ran_assignment_command assignment_command;
struct {
struct osmo_sockaddr_str remote_rtp;
bool codec_present;
enum mgcp_codecs codec;
const struct gsm0808_speech_codec_list *codec_list_bss_supported;
bool osmux_present;
uint8_t osmux_cid;
} assignment_complete;
struct {
enum gsm0808_cause bssap_cause;
uint8_t rr_cause;
const struct gsm0808_speech_codec_list *scl_bss_supported;
} assignment_failure;
struct {
enum gsm0808_cause bssap_cause;
uint8_t dlci;
} sapi_n_reject;
struct {
enum gsm0808_lcls_status status;
} lcls_status;
struct {
int todo;
} lcls_break_req;
struct ran_handover_required handover_required;
struct gsm0808_handover_required_reject handover_required_reject;
struct ran_handover_command handover_command;
struct {
enum gsm0808_cause cause;
} handover_failure;
struct ran_handover_request handover_request;
struct ran_handover_request_ack handover_request_ack;
/* MSC-A/I/T roles implement this to receive decoded NAS messages, upon feeding an L2 msgb to a ran_dec_l2_t matching the
* RAN type implementation. */
typedef int (* ran_decode_cb_t )(struct osmo_fsm_inst *caller_fi, void *caller_data, const struct ran_msg *msg);
struct ran_dec {
/* caller provided osmo_fsm_inst, used both for logging from within decoding of NAS events, as well as caller's
* context in decode_cb(). */
struct osmo_fsm_inst *caller_fi;
void *caller_data;
/* Callback receives the decoded NAS messages */
ran_decode_cb_t decode_cb;
/* NAS decoders (BSSAP/RANAP) implement this to turn a msgb into a struct ran_msg.
* An implementation typically calls ran_decoded() when done decoding.
* NAS decoding is modeled with a callback instead of a plain decoding, because some L2 messages by design contain more
* than one NAS event, e.g. Ciphering Mode Complete may include another L3 message for Identity Response, and LCLS
* Information messages can contain Status and Break Req events. */
typedef int (* ran_dec_l2_t )(struct ran_dec *ran_dec, struct msgb *l2);
int ran_decoded(struct ran_dec *ran_dec, struct ran_msg *msg);
/* An MSC-A/I/T role that receives NAS events containing DTAP buffers may use this to detect DTAP duplicates as in TS
* 24.007 Message Type Octet / Duplicate Detection */
bool ran_dec_dtap_undup_is_duplicate(struct osmo_fsm_inst *log_fi, uint8_t *n_sd_next, bool is_r99, struct msgb *l3);
/* Implemented by individual RAN implementations, see ran_a_encode() and ran_iu_encode(). */
typedef struct msgb *(* ran_encode_t )(struct osmo_fsm_inst *caller_fi, const struct ran_msg *ran_enc_msg);