Osmocom Home NodeB Gateway, for attaching femtocells to the 3G CN (OsmoMSC, OsmoSGSN) https://osmocom.org/projects/osmohnbgw
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/* IuCS/IuPS Core Network interface of HNB-GW */
/* (C) 2015 by Harald Welte <laforge@gnumonks.org>
* 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 <http://www.gnu.org/licenses/>.
*
*/
#include <arpa/inet.h>
#include <errno.h>
#include <osmocom/core/msgb.h>
#include <osmocom/core/utils.h>
#include <osmocom/core/timer.h>
#include <osmocom/sigtran/protocol/m3ua.h>
#include <osmocom/sigtran/sccp_sap.h>
#include <osmocom/sigtran/sccp_helpers.h>
#include <osmocom/hnbgw/hnbgw.h>
#include <osmocom/hnbgw/hnbgw_rua.h>
#include <osmocom/ranap/ranap_ies_defs.h>
#include <osmocom/ranap/ranap_msg_factory.h>
#include <osmocom/hnbgw/context_map.h>
#include <osmocom/hnbgw/mgw_fsm.h>
#include <osmocom/ranap/RANAP_ProcedureCode.h>
#include <osmocom/ranap/ranap_common.h>
#include <osmocom/ranap/ranap_common_ran.h>
#include <osmocom/ranap/RANAP_RANAP-PDU.h>
/***********************************************************************
* Outbound RANAP RESET to CN
***********************************************************************/
void hnbgw_cnlink_change_state(struct hnbgw_cnlink *cnlink, enum hnbgw_cnlink_state state);
static int transmit_rst(struct hnb_gw *gw, RANAP_CN_DomainIndicator_t domain,
struct osmo_sccp_addr *remote_addr)
{
struct msgb *msg;
RANAP_Cause_t cause = {
.present = RANAP_Cause_PR_transmissionNetwork,
.choice. transmissionNetwork = RANAP_CauseTransmissionNetwork_signalling_transport_resource_failure,
};
LOGP(DRANAP, LOGL_NOTICE, "Tx RESET to %s %s\n",
domain == RANAP_CN_DomainIndicator_cs_domain ? "IuCS" : "IuPS",
osmo_sccp_inst_addr_name(gw->sccp.cnlink->sccp, remote_addr));
msg = ranap_new_msg_reset(domain, &cause);
return osmo_sccp_tx_unitdata_msg(gw->sccp.cnlink->sccp_user,
&gw->sccp.local_addr,
remote_addr,
msg);
}
static int transmit_reset_ack(struct hnb_gw *gw, RANAP_CN_DomainIndicator_t domain,
const struct osmo_sccp_addr *remote_addr)
{
struct msgb *msg;
LOGP(DRANAP, LOGL_NOTICE, "Tx RESET ACK to %s %s\n",
domain == RANAP_CN_DomainIndicator_cs_domain ? "IuCS" : "IuPS",
osmo_sccp_inst_addr_name(gw->sccp.cnlink->sccp, remote_addr));
msg = ranap_new_msg_reset_ack(domain, NULL);
return osmo_sccp_tx_unitdata_msg(gw->sccp.cnlink->sccp_user,
&gw->sccp.local_addr,
remote_addr,
msg);
}
/* Timer callback once T_RafC expires */
static void cnlink_trafc_cb(void *data)
{
struct hnb_gw *gw = data;
transmit_rst(gw, RANAP_CN_DomainIndicator_cs_domain, &gw->sccp.iucs_remote_addr);
transmit_rst(gw, RANAP_CN_DomainIndicator_ps_domain, &gw->sccp.iups_remote_addr);
hnbgw_cnlink_change_state(gw->sccp.cnlink, CNLINK_S_EST_RST_TX_WAIT_ACK);
/* The spec states that we should abandon after a configurable
* number of times. We decide to simply continue trying */
}
/* change the state of a CN Link */
void hnbgw_cnlink_change_state(struct hnbgw_cnlink *cnlink, enum hnbgw_cnlink_state state)
{
switch (state) {
case CNLINK_S_NULL:
case CNLINK_S_EST_PEND:
break;
case CNLINK_S_EST_CONF:
cnlink_trafc_cb(cnlink->gw);
break;
case CNLINK_S_EST_RST_TX_WAIT_ACK:
osmo_timer_schedule(&cnlink->T_RafC, 5, 0);
break;
case CNLINK_S_EST_ACTIVE:
osmo_timer_del(&cnlink->T_RafC);
break;
}
}
/***********************************************************************
* Incoming primitives from SCCP User SAP
***********************************************************************/
static int cn_ranap_rx_reset_cmd(struct hnbgw_cnlink *cnlink,
const struct osmo_scu_unitdata_param *unitdata,
RANAP_InitiatingMessage_t *imsg)
{
RANAP_CN_DomainIndicator_t domain;
RANAP_ResetIEs_t ies;
int rc;
rc = ranap_decode_reseties(&ies, &imsg->value);
domain = ies.cN_DomainIndicator;
ranap_free_reseties(&ies);
LOGP(DRANAP, LOGL_NOTICE, "Rx RESET from %s %s, returning ACK\n",
domain == RANAP_CN_DomainIndicator_cs_domain ? "IuCS" : "IuPS",
osmo_sccp_inst_addr_name(cnlink->sccp, &unitdata->calling_addr));
/* FIXME: actually reset connections, if any */
if (transmit_reset_ack(cnlink->gw, domain, &unitdata->calling_addr))
LOGP(DRANAP, LOGL_ERROR, "Error: cannot send RESET ACK to %s %s\n",
domain == RANAP_CN_DomainIndicator_cs_domain ? "IuCS" : "IuPS",
osmo_sccp_inst_addr_name(cnlink->sccp, &unitdata->calling_addr));
return rc;
}
static int cn_ranap_rx_reset_ack(struct hnbgw_cnlink *cnlink,
RANAP_SuccessfulOutcome_t *omsg)
{
RANAP_ResetAcknowledgeIEs_t ies;
int rc;
rc = ranap_decode_resetacknowledgeies(&ies, &omsg->value);
hnbgw_cnlink_change_state(cnlink, CNLINK_S_EST_ACTIVE);
ranap_free_resetacknowledgeies(&ies);
return rc;
}
static int cn_ranap_rx_paging_cmd(struct hnbgw_cnlink *cnlink,
RANAP_InitiatingMessage_t *imsg,
const uint8_t *data, unsigned int len)
{
struct hnb_gw *gw = cnlink->gw;
struct hnb_context *hnb;
RANAP_PagingIEs_t ies;
int rc;
rc = ranap_decode_pagingies(&ies, &imsg->value);
if (rc < 0)
return rc;
/* FIXME: determine which HNBs to send this Paging command,
* rather than broadcasting to all HNBs */
llist_for_each_entry(hnb, &gw->hnb_list, list) {
rc = rua_tx_udt(hnb, data, len);
}
ranap_free_pagingies(&ies);
return 0;
}
static int cn_ranap_rx_initiating_msg(struct hnbgw_cnlink *cnlink,
const struct osmo_scu_unitdata_param *unitdata,
RANAP_InitiatingMessage_t *imsg,
const uint8_t *data, unsigned int len)
{
switch (imsg->procedureCode) {
case RANAP_ProcedureCode_id_Reset:
return cn_ranap_rx_reset_cmd(cnlink, unitdata, imsg);
case RANAP_ProcedureCode_id_Paging:
return cn_ranap_rx_paging_cmd(cnlink, imsg, data, len);
case RANAP_ProcedureCode_id_OverloadControl: /* Overload ind */
break;
case RANAP_ProcedureCode_id_ErrorIndication: /* Error ind */
break;
case RANAP_ProcedureCode_id_ResetResource: /* request */
case RANAP_ProcedureCode_id_InformationTransfer:
case RANAP_ProcedureCode_id_DirectInformationTransfer:
case RANAP_ProcedureCode_id_UplinkInformationExchange:
LOGP(DRANAP, LOGL_NOTICE, "Received unsupported RANAP "
"Procedure %ld from CN, ignoring\n", imsg->procedureCode);
break;
default:
LOGP(DRANAP, LOGL_NOTICE, "Received suspicious RANAP "
"Procedure %ld from CN, ignoring\n", imsg->procedureCode);
break;
}
return 0;
}
static int cn_ranap_rx_successful_msg(struct hnbgw_cnlink *cnlink,
RANAP_SuccessfulOutcome_t *omsg)
{
switch (omsg->procedureCode) {
case RANAP_ProcedureCode_id_Reset: /* Reset acknowledge */
return cn_ranap_rx_reset_ack(cnlink, omsg);
case RANAP_ProcedureCode_id_ResetResource: /* response */
case RANAP_ProcedureCode_id_InformationTransfer:
case RANAP_ProcedureCode_id_DirectInformationTransfer:
case RANAP_ProcedureCode_id_UplinkInformationExchange:
LOGP(DRANAP, LOGL_NOTICE, "Received unsupported RANAP "
"Procedure %ld from CN, ignoring\n", omsg->procedureCode);
break;
default:
LOGP(DRANAP, LOGL_NOTICE, "Received suspicious RANAP "
"Procedure %ld from CN, ignoring\n", omsg->procedureCode);
break;
}
return 0;
}
static int _cn_ranap_rx(struct hnbgw_cnlink *cnlink,
const struct osmo_scu_unitdata_param *unitdata,
RANAP_RANAP_PDU_t *pdu, const uint8_t *data, unsigned int len)
{
int rc;
switch (pdu->present) {
case RANAP_RANAP_PDU_PR_initiatingMessage:
rc = cn_ranap_rx_initiating_msg(cnlink, unitdata, &pdu->choice.initiatingMessage,
data, len);
break;
case RANAP_RANAP_PDU_PR_successfulOutcome:
rc = cn_ranap_rx_successful_msg(cnlink, &pdu->choice.successfulOutcome);
break;
case RANAP_RANAP_PDU_PR_unsuccessfulOutcome:
LOGP(DRANAP, LOGL_NOTICE, "Received unsupported RANAP "
"unsuccessful outcome procedure %ld from CN, ignoring\n",
pdu->choice.unsuccessfulOutcome.procedureCode);
rc = -ENOTSUP;
break;
default:
LOGP(DRANAP, LOGL_NOTICE, "Received suspicious RANAP "
"presence %u from CN, ignoring\n", pdu->present);
rc = -EINVAL;
break;
}
return rc;
}
static int handle_cn_ranap(struct hnbgw_cnlink *cnlink, const struct osmo_scu_unitdata_param *unitdata,
const uint8_t *data, unsigned int len)
{
RANAP_RANAP_PDU_t _pdu, *pdu = &_pdu;
asn_dec_rval_t dec_ret;
int rc;
memset(pdu, 0, sizeof(*pdu));
dec_ret = aper_decode(NULL, &asn_DEF_RANAP_RANAP_PDU, (void **) &pdu,
data, len, 0, 0);
if (dec_ret.code != RC_OK) {
LOGP(DRANAP, LOGL_ERROR, "Error in RANAP ASN.1 decode\n");
return -1;
}
rc = _cn_ranap_rx(cnlink, unitdata, pdu, data, len);
return rc;
}
static bool pc_and_ssn_match(const struct osmo_sccp_addr *a, const struct osmo_sccp_addr *b)
{
return (a == b)
|| ((a->pc == b->pc)
&& (a->ssn == b->ssn));
}
static int classify_cn_remote_addr(const struct hnb_gw *gw,
const struct osmo_sccp_addr *cn_remote_addr,
bool *is_ps)
{
if (pc_and_ssn_match(cn_remote_addr, &gw->sccp.iucs_remote_addr)) {
if (is_ps)
*is_ps = false;
return 0;
}
if (pc_and_ssn_match(cn_remote_addr, &gw->sccp.iups_remote_addr)) {
if (is_ps)
*is_ps = true;
return 0;
}
LOGP(DMAIN, LOGL_ERROR, "Unexpected remote address, matches neither CS nor PS address: %s\n",
osmo_sccp_addr_dump(cn_remote_addr));
return -1;
}
static int handle_cn_unitdata(struct hnbgw_cnlink *cnlink,
const struct osmo_scu_unitdata_param *param,
struct osmo_prim_hdr *oph)
{
if (param->called_addr.ssn != OSMO_SCCP_SSN_RANAP) {
LOGP(DMAIN, LOGL_NOTICE, "N-UNITDATA.ind for unknown SSN %u\n",
param->called_addr.ssn);
return -1;
}
if (classify_cn_remote_addr(cnlink->gw, &param->calling_addr, NULL) < 0)
return -1;
return handle_cn_ranap(cnlink, param, msgb_l2(oph->msg), msgb_l2len(oph->msg));
}
static int handle_cn_conn_conf(struct hnbgw_cnlink *cnlink,
const struct osmo_scu_connect_param *param,
struct osmo_prim_hdr *oph)
{
struct osmo_ss7_instance *ss7 = osmo_sccp_get_ss7(cnlink->gw->sccp.client);
LOGP(DMAIN, LOGL_DEBUG, "handle_cn_conn_conf() conn_id=%d, addrs: called=%s calling=%s responding=%s\n",
param->conn_id,
osmo_sccp_addr_to_str_c(OTC_SELECT, ss7, &param->called_addr),
osmo_sccp_addr_to_str_c(OTC_SELECT, ss7, &param->calling_addr),
osmo_sccp_addr_to_str_c(OTC_SELECT, ss7, &param->responding_addr));
/* Nothing needs to happen for RUA, RUA towards the HNB doesn't seem to know any confirmations to its CONNECT
* operation. */
/* If our initial SCCP CR was sent without data payload, then the initial RANAP message is cached and waiting to
* be sent as soon as the SCCP connection is confirmed. See if that is the case, send cached data. */
context_map_send_cached_msg(context_map_by_cn(cnlink, param->conn_id));
return 0;
}
static int handle_cn_data_ind(struct hnbgw_cnlink *cnlink,
const struct osmo_scu_data_param *param,
struct osmo_prim_hdr *oph)
{
struct hnbgw_context_map *map;
ranap_message *message;
int rc;
/* Usually connection-oriented data is always passed transparently towards the specific HNB, via a RUA
* connection identified by conn_id. An exception is made for RANAP RAB AssignmentRequest and
* RANAP RAB AssignmentResponse, since those messages contain transport layer information (RTP stream IP/Port),
* which is rewritten by the FSM that controls the co-located media gateway. */
map = context_map_by_cn(cnlink, param->conn_id);
if (!map) {
/* FIXME: Return an error / released primitive */
return 0;
}
/* Intercept RAB Assignment Request, Setup MGW FSM */
if (!map->is_ps) {
message = talloc_zero(map, ranap_message);
rc = ranap_ran_rx_co_decode(map, message, msgb_l2(oph->msg), msgb_l2len(oph->msg));
if (rc == 0) {
switch (message->procedureCode) {
case RANAP_ProcedureCode_id_RAB_Assignment:
/* mgw_fsm_alloc_and_handle_rab_ass_req() takes ownership of (ranap) message */
return handle_rab_ass_req(map, oph, message);
case RANAP_ProcedureCode_id_Iu_Release:
/* Any IU Release will terminate the MGW FSM, the message itsself is not passed to the
* FSM code. It is just forwarded normally by the rua_tx_dt() call below. */
mgw_fsm_release(map);
break;
}
ranap_ran_rx_co_free(message);
}
talloc_free(message);
}
return rua_tx_dt(map->hnb_ctx, map->is_ps, map->rua_ctx_id,
msgb_l2(oph->msg), msgb_l2len(oph->msg));
}
static int handle_cn_disc_ind(struct hnbgw_cnlink *cnlink,
const struct osmo_scu_disconn_param *param,
struct osmo_prim_hdr *oph)
{
struct hnbgw_context_map *map;
LOGP(DMAIN, LOGL_DEBUG, "handle_cn_disc_ind() conn_id=%d originator=%d\n",
param->conn_id, param->originator);
LOGP(DMAIN, LOGL_DEBUG, "handle_cn_disc_ind() responding_addr=%s\n",
inet_ntoa(param->responding_addr.ip.v4));
RUA_Cause_t rua_cause = {
.present = RUA_Cause_PR_NOTHING,
/* FIXME: Convert incoming SCCP cause to RUA cause */
};
/* we need to notify the HNB associated with this connection via
* a RUA DISCONNECT */
map = context_map_by_cn(cnlink, param->conn_id);
if (!map) {
/* FIXME: Return an error / released primitive */
return 0;
}
return rua_tx_disc(map->hnb_ctx, map->is_ps, map->rua_ctx_id,
&rua_cause, msgb_l2(oph->msg), msgb_l2len(oph->msg));
}
/* Entry point for primitives coming up from SCCP User SAP */
static int sccp_sap_up(struct osmo_prim_hdr *oph, void *ctx)
{
struct osmo_sccp_user *scu = ctx;
struct hnbgw_cnlink *cnlink;
struct osmo_scu_prim *prim = (struct osmo_scu_prim *) oph;
int rc = 0;
LOGP(DMAIN, LOGL_DEBUG, "sccp_sap_up(%s)\n", osmo_scu_prim_name(oph));
if (!scu) {
LOGP(DMAIN, LOGL_ERROR,
"sccp_sap_up(): NULL osmo_sccp_user, cannot send prim (sap %u prim %u op %d)\n",
oph->sap, oph->primitive, oph->operation);
return -1;
}
cnlink = osmo_sccp_user_get_priv(scu);
if (!cnlink) {
LOGP(DMAIN, LOGL_ERROR,
"sccp_sap_up(): NULL hnbgw_cnlink, cannot send prim (sap %u prim %u op %d)\n",
oph->sap, oph->primitive, oph->operation);
return -1;
}
switch (OSMO_PRIM_HDR(oph)) {
case OSMO_PRIM(OSMO_SCU_PRIM_N_UNITDATA, PRIM_OP_INDICATION):
rc = handle_cn_unitdata(cnlink, &prim->u.unitdata, oph);
break;
case OSMO_PRIM(OSMO_SCU_PRIM_N_CONNECT, PRIM_OP_CONFIRM):
rc = handle_cn_conn_conf(cnlink, &prim->u.connect, oph);
break;
case OSMO_PRIM(OSMO_SCU_PRIM_N_DATA, PRIM_OP_INDICATION):
rc = handle_cn_data_ind(cnlink, &prim->u.data, oph);
break;
case OSMO_PRIM(OSMO_SCU_PRIM_N_DISCONNECT, PRIM_OP_INDICATION):
rc = handle_cn_disc_ind(cnlink, &prim->u.disconnect, oph);
break;
default:
LOGP(DMAIN, LOGL_ERROR,
"Received unknown prim %u from SCCP USER SAP\n",
OSMO_PRIM_HDR(oph));
break;
}
msgb_free(oph->msg);
return rc;
}
static bool addr_has_pc_and_ssn(const struct osmo_sccp_addr *addr)
{
if (!(addr->presence & OSMO_SCCP_ADDR_T_SSN))
return false;
if (!(addr->presence & OSMO_SCCP_ADDR_T_PC))
return false;
return true;
}
static int resolve_addr_name(struct osmo_sccp_addr *dest, struct osmo_ss7_instance **ss7,
const char *addr_name, const char *label,
uint32_t default_pc)
{
struct osmo_ss7_instance *ss7_tmp;
if (!addr_name) {
osmo_sccp_make_addr_pc_ssn(dest, default_pc, OSMO_SCCP_SSN_RANAP);
LOGP(DMAIN, LOGL_INFO, "%s remote addr not configured, using default: %s\n", label,
osmo_sccp_addr_name(*ss7, dest));
return 0;
}
ss7_tmp = osmo_sccp_addr_by_name(dest, addr_name);
if (!ss7_tmp) {
LOGP(DMAIN, LOGL_ERROR, "%s remote addr: no such SCCP address book entry: '%s'\n",
label, addr_name);
return -1;
}
if (*ss7 && (*ss7 != ss7_tmp)) {
LOGP(DMAIN, LOGL_ERROR, "IuCS and IuPS cannot be served from separate CS7 instances,"
" cs7 instance %d != %d\n", (*ss7)->cfg.id, ss7_tmp->cfg.id);
return -1;
}
*ss7 = ss7_tmp;
osmo_sccp_addr_set_ssn(dest, OSMO_SCCP_SSN_RANAP);
if (!addr_has_pc_and_ssn(dest)) {
LOGP(DMAIN, LOGL_ERROR, "Invalid/incomplete %s remote-addr: %s\n",
label, osmo_sccp_addr_name(*ss7, dest));
return -1;
}
LOGP(DRANAP, LOGL_NOTICE, "Remote %s SCCP addr: %s\n",
label, osmo_sccp_addr_name(*ss7, dest));
return 0;
}
int hnbgw_cnlink_init(struct hnb_gw *gw, const char *stp_host, uint16_t stp_port, const char *local_ip)
{
struct hnbgw_cnlink *cnlink;
struct osmo_ss7_instance *ss7;
uint32_t local_pc;
OSMO_ASSERT(!gw->sccp.client);
OSMO_ASSERT(!gw->sccp.cnlink);
ss7 = NULL;
if (resolve_addr_name(&gw->sccp.iucs_remote_addr, &ss7,
gw->config.iucs_remote_addr_name, "IuCS", (23 << 3) + 1))
return -1;
if (resolve_addr_name(&gw->sccp.iups_remote_addr, &ss7,
gw->config.iups_remote_addr_name, "IuPS", (23 << 3) + 4))
return -1;
if (!ss7) {
LOGP(DRANAP, LOGL_NOTICE, "No cs7 instance configured for IuCS nor IuPS,"
" creating default instance\n");
ss7 = osmo_ss7_instance_find_or_create(gw, 0);
ss7->cfg.primary_pc = (23 << 3) + 5;
}
if (!osmo_ss7_pc_is_valid(ss7->cfg.primary_pc)) {
LOGP(DMAIN, LOGL_ERROR, "IuCS/IuPS uplink cannot be setup: CS7 instance %d has no point-code set\n",
ss7->cfg.id);
return -1;
}
local_pc = ss7->cfg.primary_pc;
osmo_sccp_make_addr_pc_ssn(&gw->sccp.local_addr, local_pc, OSMO_SCCP_SSN_RANAP);
LOGP(DRANAP, LOGL_NOTICE, "Local SCCP addr: %s\n", osmo_sccp_addr_name(ss7, &gw->sccp.local_addr));
gw->sccp.client = osmo_sccp_simple_client_on_ss7_id(gw, ss7->cfg.id, "OsmoHNBGW",
local_pc, OSMO_SS7_ASP_PROT_M3UA,
0, local_ip, stp_port, stp_host);
if (!gw->sccp.client) {
LOGP(DMAIN, LOGL_ERROR, "Failed to init SCCP Client\n");
return -1;
}
cnlink = talloc_zero(gw, struct hnbgw_cnlink);
cnlink->gw = gw;
INIT_LLIST_HEAD(&cnlink->map_list);
cnlink->T_RafC.cb = cnlink_trafc_cb;
cnlink->T_RafC.data = gw;
cnlink->next_conn_id = 1000;
cnlink->sccp_user = osmo_sccp_user_bind_pc(gw->sccp.client, "OsmoHNBGW", sccp_sap_up,
OSMO_SCCP_SSN_RANAP, gw->sccp.local_addr.pc);
if (!cnlink->sccp_user) {
LOGP(DMAIN, LOGL_ERROR, "Failed to init SCCP User\n");
return -1;
}
LOGP(DRANAP, LOGL_NOTICE, "Remote SCCP addr: IuCS: %s\n",
osmo_sccp_addr_name(ss7, &gw->sccp.iucs_remote_addr));
LOGP(DRANAP, LOGL_NOTICE, "Remote SCCP addr: IuPS: %s\n",
osmo_sccp_addr_name(ss7, &gw->sccp.iups_remote_addr));
/* In sccp_sap_up() we expect the cnlink in the user's priv. */
osmo_sccp_user_set_priv(cnlink->sccp_user, cnlink);
gw->sccp.cnlink = cnlink;
return 0;
}