281 lines
13 KiB
C
281 lines
13 KiB
C
/* The RAN (Radio Access Network) side of an A- or Iu-connection, which is closely tied to an SCCP connection.
|
|
* (as opposed to the NAS side.)
|
|
*
|
|
* The SCCP connection is located with the MSC-I role, while the MSC-A responsible for subscriber management may be at a
|
|
* remote MSC behind an E-interface connection. In that case we need to forward the L2 messages over the E-interface and
|
|
* the BSSAP or RANAP messages get decoded and interpreted at MSC-A.
|
|
*
|
|
* The life cycle of a DTAP message from RAN to MSC-A -- starting from the bottom left:
|
|
*
|
|
* ------------------>[ 3GPP TS 24.008 ]------------------->|
|
|
* ^ (Request) (Response) |
|
|
* | v
|
|
* msc_a_up_l3() msc_a_tx_dtap_to_i(dtap_msgb)
|
|
* ^ |
|
|
* | v
|
|
* msc_a_ran_decode_cb(struct ran_dec_msg) msc_a_ran_enc(struct ran_enc_msg)
|
|
* ^ ^ . |
|
|
* | -Decode NAS- | . NAS v
|
|
* | | . ran_infra[type]->ran_encode(struct ran_enc_msg)
|
|
* ran_a_decode_l2() ran_iu_decode_l2() . | |
|
|
* ^ ^ . v v
|
|
* | | . ran_a_encode() ran_iu_encode()
|
|
* ran_infra[type]->ran_dec_l2() | |
|
|
* ^ | -Encode BSSAP/RANAP- |
|
|
* | v v
|
|
* msc_a_ran_dec() msub_tx_an_apdu(from MSC_ROLE_A to MSC_ROLE_I)
|
|
* ^ |
|
|
* | MSC-A v
|
|
* . msc_a FSM . . . . . . . . . . . . . . . . msc_a FSM . . . . . . . . . .
|
|
* ^ |
|
|
* | MSC_A_EV_FROM_I_PROCESS_ACCESS_SIGNALLING_REQUEST v
|
|
* | data = an_apdu [possibly
|
|
* | via GSUP
|
|
* [possibly from remote MSC-A]
|
|
* via GSUP |
|
|
* to remote MSC-A] | MSC_I_EV_FROM_A_FORWARD_ACCESS_SIGNALLING_REQUEST
|
|
* ^ | data = an_apdu
|
|
* | v
|
|
* . msc_i FSM . . . . . . . . . . . . . . . . msc_i FSM . . . . . . . . . .
|
|
* ^ MSC-I |
|
|
* | MSC_EV_FROM_RAN_UP_L2 V
|
|
* | data = an_apdu msc_i_down_l2(an_apdu->msg)
|
|
* | |
|
|
* ran_peer FSM V
|
|
* ^ ran_conn_down_l2_co();
|
|
* | RAN_PEER_EV_MSG_UP_CO |
|
|
* | data = struct ran_peer_ev_ctx | RAN_PEER_EV_MSG_DOWN_CO
|
|
* | | data = struct ran_peer_ev_ctx
|
|
* ran_peer_up_l2() V
|
|
* (ran_infa->sccp_ran_ops.up_l2) ran_peer FSM
|
|
* ^ ^ |
|
|
* | | v
|
|
* sccp_ran_sap_up() sccp_ran_down_l2_co(conn_id, msg)
|
|
* ^ ^ | |
|
|
* | | |SCCP|
|
|
* |SCCP| v v
|
|
* | | <------------------------------------------------------
|
|
* BSC RNC
|
|
* | |
|
|
* BTS NodeB
|
|
* | |
|
|
* MS UE
|
|
*
|
|
* sccp_ran:
|
|
* - handles receiving of SCCP primitives from the SCCP layer.
|
|
* - extracts L2 msg
|
|
* - passes on L2 msg and conn_id by calling sccp_ran_ops.up_l2 == ran_peer_up_l2().
|
|
*
|
|
* On Connection-Oriented *Initial* message
|
|
* ========================================
|
|
*
|
|
* ran_peer_up_l2()
|
|
* - notices an unknown, new osmo_rat_type:conn_id and
|
|
* - first creates an "empty" msub with new local MSC-I and MSC-A roles;
|
|
* in this case always a *local* MSC-A (never remote on Initial messages).
|
|
* - Passes the L2 msgb containing the BSSAP or RANAP as AN-APDU
|
|
* in MSC_A_EV_FROM_I_COMPLETE_LAYER_3 to the MSC-A role FSM instance.
|
|
*
|
|
* MSC-A:
|
|
* - Receives MSC_A_EV_FROM_I_COMPLETE_LAYER_3 AN-APDU, notices an_proto indicating BSSAP or RANAP.
|
|
* - Passes L2 message to ran_infra[]->ran_dec_l2(), which decodes the BSSAP or RANAP.
|
|
* - contained information is passed to msc_a_ran_decode_cb().
|
|
* - which msc_a starts Complete-L3 and VLR procedures,
|
|
* - associates msub with a vlr_subscr,
|
|
* - sends DTAP requests back down by calling msc_a_tx_dtap_to_i() (possibly other more specialized tx functions)
|
|
* - according to ran_infra[]->ran_encode(), the ran_enc_msg gets encoded as BSSAP or RANAP.
|
|
* - passes as AN-APDU to MSC-I in MSC_I_EV_FROM_A_FORWARD_ACCESS_SIGNALLING_REQUEST signal.
|
|
*
|
|
* MSC-I, receiving AN-APDU from local MSC-A:
|
|
* - feeds L2 msgb to the ran_peer FSM as RAN_PEER_EV_MSG_DOWN_CO, passing the SCCP conn_id.
|
|
*
|
|
* sccp_ran_down_l2_co()
|
|
* - wraps in SCCP prim,
|
|
* - sends down.
|
|
*
|
|
*
|
|
* On (non-Initial) Connection-Oriented DTAP
|
|
* =========================================
|
|
*
|
|
* ran_peer_up_l2()
|
|
* - notices an already known conn_id by looking up a matching osmo_rat_type:ran_conn.
|
|
* - ran_conn already associated with an MSC-I role.
|
|
* - Now forwards AN-APDU like above, only using MSC_A_EV_FROM_I_PROCESS_ACCESS_SIGNALLING_REQUEST.
|
|
*
|
|
*
|
|
* MSC-A and MSC-I roles on separate MSC instances
|
|
* ===============================================
|
|
*
|
|
* After inter-MSC handover, the MSC-I and MSC-A roles can be on separate MSC instances, typically physically distant /
|
|
* possibly belonging to a different operator. This will never see Complete-L3.
|
|
* Assuming that both instances are osmo-msc, then:
|
|
*
|
|
* At MSC-B:
|
|
* initially, via GSUP:
|
|
* - receives Handover Request from remote MSC-A,
|
|
* - creates msub with local MSC-T role,
|
|
* - sets up the ran_conn with a new SCCP conn_id, and waits for the MS/UE to show up.
|
|
* - (fast-forward to successful Handover)
|
|
* - MSC-T role becomes MSC-I for the remote MSC-A.
|
|
*
|
|
* Then for DTAP from the MS:
|
|
*
|
|
* sccp_ran:
|
|
* - receives SCCP,
|
|
* - extracts L2 and passes on to ran_peer_up_l2().
|
|
*
|
|
* ran_peer_up_l2()
|
|
* - notices an already known conn_id by looking up a matching ran_conn.
|
|
* - ran_conn already associated with an MSC-I role and an msub.
|
|
* - forwards AN-APDU in MSC_A_EV_FROM_I_PROCESS_ACCESS_SIGNALLING_REQUEST to the MSC-A role.
|
|
*
|
|
* At MSC-B, the "MSC-A role" is a *remote* implementation,
|
|
* meaning there is an msc_a_remote FSM instance in MSC-B's msub:
|
|
*
|
|
* MSC-A-Remote:
|
|
* - msc_a_remote receives MSC_A_EV_FROM_I_PROCESS_ACCESS_SIGNALLING_REQUEST,
|
|
* - wraps AN-APDU in GSUP message,
|
|
* - sends to remote MSC-A.
|
|
*
|
|
* At MSC-A:
|
|
* Here, msub has a *remote* MSC-I role,
|
|
* meaning it is an msc_i_remote FSM instance:
|
|
*
|
|
* MSC-I-Remote:
|
|
* - msc_i_remote receives and decodes GSUP message,
|
|
* - passes AN-APDU to MSC-A FSM instance via MSC_A_EV_FROM_I_PROCESS_ACCESS_SIGNALLING_REQUEST.
|
|
*
|
|
* MSC-A role:
|
|
* - Receives MSC_A_EV_FROM_I_PROCESS_ACCESS_SIGNALLING_REQUEST, notices an_proto indicating BSSAP or RANAP.
|
|
* - Passes L2 message to ran_infra[]->ran_dec_l2(), which decodes the BSSAP or RANAP.
|
|
* - contained information is passed to msc_a_ran_decode_cb().
|
|
* - sends DTAP requests back down by calling msc_a_tx_dtap_to_i() (possibly other more specialized tx functions)
|
|
* - according to ran_infra[]->ran_encode(), the ran_enc_msg gets encoded as BSSAP or RANAP.
|
|
* - passes as AN-APDU to MSC-I in MSC_I_EV_FROM_A_FORWARD_ACCESS_SIGNALLING_REQUEST signal.
|
|
*
|
|
* MSC-I-Remote:
|
|
* - msc_i_remote wraps AN-APDU in GSUP message,
|
|
* - sends to MSC-B
|
|
*
|
|
* At MSC-B:
|
|
* MSC-A-Remote:
|
|
* - msc_a_remote receives GSUP message,
|
|
* - passes AN-APDU to msc_i in MSC_I_EV_FROM_A_FORWARD_ACCESS_SIGNALLING_REQUEST.
|
|
*
|
|
* MSC-I:
|
|
* - BSSAP or RANAP is indicated both by the AN-APDU an_proto, as well as the ran_conn state for that subscriber.
|
|
* - feeds L2 msgb to the ran_peer FSM as RAN_PEER_EV_MSG_DOWN_CO, passing the SCCP conn_id.
|
|
*
|
|
* sccp_ran_down_l2_co()
|
|
* - wraps in SCCP prim,
|
|
* - sends down.
|
|
*
|
|
*/
|
|
|
|
#pragma once
|
|
|
|
#include <stdint.h>
|
|
|
|
#include <osmocom/core/tdef.h>
|
|
#include <osmocom/gsm/gsm_utils.h>
|
|
#include <osmocom/gsm/gsm0808_utils.h>
|
|
#include <osmocom/sigtran/sccp_sap.h>
|
|
|
|
#include <osmocom/msc/paging.h>
|
|
|
|
struct msgb;
|
|
struct ran_infra;
|
|
struct sccp_ran_inst;
|
|
|
|
#define LOG_SCCP_RAN_CO(sri, peer_addr, conn_id, level, fmt, args...) \
|
|
LOGP((sri) && (sri)->ran? (sri)->ran->log_subsys : DMSC, level, "(%s-%u%s%s) " fmt, \
|
|
osmo_rat_type_name((sri) && (sri)->ran ? (sri)->ran->type : OSMO_RAT_UNKNOWN), conn_id, \
|
|
peer_addr ? " from " : "", \
|
|
peer_addr ? osmo_sccp_inst_addr_name((sri)->sccp, peer_addr) : "", \
|
|
## args)
|
|
|
|
#define LOG_SCCP_RAN_CL_CAT(sri, peer_addr, subsys, level, fmt, args...) \
|
|
LOGP(subsys, level, "(%s%s%s) " fmt, \
|
|
osmo_rat_type_name((sri) && (sri)->ran ? (sri)->ran->type : OSMO_RAT_UNKNOWN), \
|
|
peer_addr ? " from " : "", \
|
|
peer_addr ? osmo_sccp_inst_addr_name((sri)->sccp, peer_addr) : "", \
|
|
## args)
|
|
|
|
#define LOG_SCCP_RAN_CL(sri, peer_addr, level, fmt, args...) \
|
|
LOG_SCCP_RAN_CL_CAT(sri, peer_addr, (sri) && (sri)->ran? (sri)->ran->log_subsys : DMSC, level, fmt, ##args)
|
|
|
|
#define LOG_SCCP_RAN_CAT(sri, subsys, level, fmt, args...) \
|
|
LOG_SCCP_RAN_CL_CAT(sri, NULL, subsys, level, fmt, ##args)
|
|
|
|
#define LOG_SCCP_RAN(sri, level, fmt, args...) \
|
|
LOG_SCCP_RAN_CL(sri, NULL, level, fmt, ##args)
|
|
|
|
extern struct osmo_tdef g_sccp_tdefs[];
|
|
|
|
enum reset_msg_type {
|
|
SCCP_RAN_MSG_NON_RESET = 0,
|
|
SCCP_RAN_MSG_RESET,
|
|
SCCP_RAN_MSG_RESET_ACK,
|
|
};
|
|
|
|
struct sccp_ran_ops {
|
|
/* Implemented to receive L2 messages (e.g. BSSAP or RANAP passed to ran_peer).
|
|
* - ConnectionLess messages: co = false, calling_addr != NULL, conn_id == 0;
|
|
* - ConnectionOriented Initial messages: co = true, calling_addr != NULL;
|
|
* - ConnectionOriented non-Initial messages: co = true, calling_addr == NULL;
|
|
*/
|
|
int (* up_l2 )(struct sccp_ran_inst *sri, const struct osmo_sccp_addr *calling_addr, bool co, uint32_t conn_id,
|
|
struct msgb *l2);
|
|
|
|
/* Implemented to finally remove a connection state. Last event in a connection-oriented exchange. If the
|
|
* N-DISCONNECT contained l2 data, it was dispatched via up_l2() before this is called. */
|
|
void (* disconnect )(struct sccp_ran_inst *sri, uint32_t conn_id);
|
|
|
|
/* Return whether the given l2_cl message is a RESET, RESET ACKNOWLEDGE, or RESET-unrelated message.
|
|
* This callback is stored in struct sccp_ran_inst to provide RESET handling to the caller (ran_peer),
|
|
* it is not used in sccp_ran.c. */
|
|
enum reset_msg_type (* is_reset_msg )(const struct sccp_ran_inst *sri, const struct msgb *l2_cl);
|
|
|
|
/* Return a RESET or RESET ACK message for this RAN type.
|
|
* This callback is stored in struct sccp_ran_inst to provide RESET handling to the caller (ran_peer),
|
|
* it is not used in sccp_ran.c. */
|
|
struct msgb* (* make_reset_msg )(const struct sccp_ran_inst *sri, enum reset_msg_type);
|
|
|
|
/* Return a PAGING message towards the given Cell Identifier, to page for the given TMSI or IMSI.
|
|
* Page for TMSI if TMSI != GSM_RESERVED_TMSI, otherwise page for IMSI. */
|
|
struct msgb* (* 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);
|
|
|
|
/* Return a human printable name for the msgb */
|
|
const char* (* msg_name )(const struct sccp_ran_inst *sri, const struct msgb *l2);
|
|
};
|
|
|
|
struct sccp_ran_inst {
|
|
struct ran_infra *ran;
|
|
|
|
struct osmo_sccp_instance *sccp;
|
|
struct osmo_sccp_user *scu;
|
|
struct osmo_sccp_addr local_sccp_addr;
|
|
|
|
struct llist_head ran_peers;
|
|
struct llist_head ran_conns;
|
|
|
|
void *user_data;
|
|
|
|
/* Compatibility with legacy osmo-hnbgw that was unable to properly handle RESET messages. Set to 'false' to
|
|
* require proper RESET procedures, set to 'true' to implicitly put a ran_peer in RAN_PEER_ST_READY upon the
|
|
* first CO message. Default is false = be strict. */
|
|
bool ignore_missing_reset;
|
|
};
|
|
|
|
struct sccp_ran_inst *sccp_ran_init(void *talloc_ctx, struct osmo_sccp_instance *sccp, enum osmo_sccp_ssn ssn,
|
|
const char *sccp_user_name, struct ran_infra *ran, void *user_data);
|
|
|
|
int sccp_ran_down_l2_co_initial(struct sccp_ran_inst *sri,
|
|
const struct osmo_sccp_addr *called_addr,
|
|
uint32_t conn_id, struct msgb *l2);
|
|
int sccp_ran_down_l2_co(struct sccp_ran_inst *sri, uint32_t conn_id, struct msgb *l2);
|
|
int sccp_ran_down_l2_cl(struct sccp_ran_inst *sri, const struct osmo_sccp_addr *called_addr, struct msgb *l2);
|
|
|
|
int sccp_ran_disconnect(struct sccp_ran_inst *ran, uint32_t conn_id, uint32_t cause);
|