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srsLTE/srsenb/src/stack/s1ap/s1ap.cc

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/**
* Copyright 2013-2022 Software Radio Systems Limited
*
* This file is part of srsRAN.
*
* srsRAN 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.
*
* srsRAN 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.
*
* A copy of the GNU Affero General Public License can be found in
* the LICENSE file in the top-level directory of this distribution
* and at http://www.gnu.org/licenses/.
*
*/
#include "srsenb/hdr/stack/s1ap/s1ap.h"
#include "srsran/adt/scope_exit.h"
#include "srsran/common/bcd_helpers.h"
#include "srsran/common/enb_events.h"
#include "srsran/common/int_helpers.h"
#include "srsran/common/standard_streams.h"
#include "srsran/interfaces/enb_rrc_interface_s1ap.h"
#include <arpa/inet.h> //for inet_ntop()
#include <inttypes.h>
#include <netinet/in.h>
#include <netinet/sctp.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
using srsran::s1ap_mccmnc_to_plmn;
using srsran::uint32_to_uint8;
#define procError(fmt, ...) s1ap_ptr->logger.error("Proc \"%s\" - " fmt, name(), ##__VA_ARGS__)
#define procWarning(fmt, ...) s1ap_ptr->logger.warning("Proc \"%s\" - " fmt, name(), ##__VA_ARGS__)
#define procInfo(fmt, ...) s1ap_ptr->logger.info("Proc \"%s\" - " fmt, name(), ##__VA_ARGS__)
#define procDebug(fmt, ...) s1ap_ptr->logger.debug("Proc \"%s\" - " fmt, name(), ##__VA_ARGS__)
#define WarnUnsupportFeature(cond, featurename) \
do { \
if (cond) { \
logger.warning("Not handling feature - %s", featurename); \
} \
} while (0)
using namespace asn1::s1ap;
namespace srsenb {
/*************************
* Helper Functions
************************/
asn1::bounded_bitstring<1, 160, true, true> addr_to_asn1(const char* addr_str)
{
asn1::bounded_bitstring<1, 160, true, true> transport_layer_addr(32);
uint8_t addr[4];
if (inet_pton(AF_INET, addr_str, addr) != 1) {
srsran::console("Invalid addr_str: %s\n", addr_str);
perror("inet_pton");
}
for (uint32_t j = 0; j < 4; ++j) {
transport_layer_addr.data()[j] = addr[3 - j];
}
return transport_layer_addr;
}
/// Helper to add ERAB items that are duplicates in the received S1AP message
template <typename List>
void add_repeated_erab_ids(const List& list,
srsran::bounded_vector<erab_item_s, ASN1_S1AP_MAXNOOF_ERABS>& failed_cfg_erabs)
{
for (auto it = list.begin(); it != list.end(); ++it) {
for (auto it2 = it + 1; it2 != list.end(); ++it2) {
if (equal_obj_id(*it, *it2)) {
failed_cfg_erabs.push_back(erab_item_s());
failed_cfg_erabs.back().erab_id = get_obj_id(*it);
failed_cfg_erabs.back().cause.set_radio_network().value = cause_radio_network_opts::multiple_erab_id_instances;
}
}
}
// Sort and remove duplications
std::sort(failed_cfg_erabs.begin(), failed_cfg_erabs.end(), &lower_obj_id<erab_item_s>);
failed_cfg_erabs.erase(std::unique(failed_cfg_erabs.begin(), failed_cfg_erabs.end(), &equal_obj_id<erab_item_s>),
failed_cfg_erabs.end());
}
bool contains_erab_id(srsran::bounded_vector<erab_item_s, ASN1_S1AP_MAXNOOF_ERABS>& failed_cfg_erabs, uint16_t erab_id)
{
erab_item_s dummy;
dummy.erab_id = erab_id;
return std::find_if(failed_cfg_erabs.begin(), failed_cfg_erabs.end(), [erab_id](const erab_item_s& e) {
return e.erab_id == erab_id;
}) != failed_cfg_erabs.end();
}
void sanitize_response_erab_lists(s1ap::erab_item_list& failed_cfg_erabs, s1ap::erab_id_list& erabs)
{
// Sort and remove duplicates
std::sort(failed_cfg_erabs.begin(), failed_cfg_erabs.end(), &lower_obj_id<erab_item_s>);
failed_cfg_erabs.erase(std::unique(failed_cfg_erabs.begin(), failed_cfg_erabs.end(), &equal_obj_id<erab_item_s>),
failed_cfg_erabs.end());
std::sort(erabs.begin(), erabs.end());
erabs.erase(std::unique(erabs.begin(), erabs.end()), erabs.end());
}
template <typename OutList>
void fill_erab_failed_setup_list(OutList& output_list, const s1ap::erab_item_list& input_list)
{
output_list.resize(input_list.size());
for (size_t i = 0; i < input_list.size(); ++i) {
output_list[i].load_info_obj(ASN1_S1AP_ID_ERAB_ITEM);
output_list[i]->erab_item() = input_list[i];
}
}
/*********************************************************
* TS 36.413 - Section 8.4.1 - "Handover Preparation"
*********************************************************/
s1ap::ue::ho_prep_proc_t::ho_prep_proc_t(s1ap::ue* ue_) : ue_ptr(ue_), s1ap_ptr(ue_->s1ap_ptr) {}
srsran::proc_outcome_t s1ap::ue::ho_prep_proc_t::init(uint32_t target_eci_,
uint16_t target_tac_,
srsran::plmn_id_t target_plmn_,
srsran::span<uint32_t> fwd_erabs,
srsran::unique_byte_buffer_t rrc_container_,
bool has_direct_fwd_path)
{
ho_cmd_msg = nullptr;
target_eci = target_eci_;
target_tac = target_tac_;
target_plmn = target_plmn_;
procInfo("Sending HandoverRequired to MME id=%d", ue_ptr->ctxt.mme_ue_s1ap_id.value());
if (not ue_ptr->send_ho_required(
target_eci, target_tac, target_plmn, fwd_erabs, std::move(rrc_container_), has_direct_fwd_path)) {
procError("Failed to send HORequired to cell 0x%x", target_eci);
return srsran::proc_outcome_t::error;
}
// Start HO preparation timer
ue_ptr->ts1_reloc_prep.run();
return srsran::proc_outcome_t::yield;
}
srsran::proc_outcome_t s1ap::ue::ho_prep_proc_t::react(ts1_reloc_prep_expired e)
{
// do nothing for now
procError("timer TS1Relocprep has expired.");
return srsran::proc_outcome_t::error;
}
srsran::proc_outcome_t s1ap::ue::ho_prep_proc_t::react(const ho_prep_fail_s& msg)
{
ue_ptr->ts1_reloc_prep.stop();
std::string cause = s1ap_ptr->get_cause(msg->cause.value);
procError("HO preparation Failure. Cause: %s", cause.c_str());
srsran::console("HO preparation Failure. Cause: %s\n", cause.c_str());
return srsran::proc_outcome_t::error;
}
/**
* TS 36.413 - Section 8.4.1.2 - HandoverPreparation Successful Operation
* Description: MME returns back an HandoverCommand to the SeNB
*/
srsran::proc_outcome_t s1ap::ue::ho_prep_proc_t::react(const asn1::s1ap::ho_cmd_s& msg)
{
// update timers
ue_ptr->ts1_reloc_prep.stop();
ue_ptr->ts1_reloc_overall.run();
// Check for unsupported S1AP fields
if (msg.ext or msg->target_to_source_transparent_container_secondary_present or
msg->handov_type.value.value != handov_type_opts::intralte or msg->crit_diagnostics_present or
msg->nas_security_paramsfrom_e_utran_present) {
procWarning("Not handling HandoverCommand extensions and non-intraLTE params");
}
// In case of intra-system Handover, Target to Source Transparent Container IE shall be encoded as
// Target eNB to Source eNB Transparent Container IE
asn1::cbit_ref bref(msg->target_to_source_transparent_container.value.data(),
msg->target_to_source_transparent_container.value.size());
asn1::s1ap::targetenb_to_sourceenb_transparent_container_s container;
if (container.unpack(bref) != asn1::SRSASN_SUCCESS) {
procError("Failed to decode TargeteNBToSourceeNBTransparentContainer");
return srsran::proc_outcome_t::error;
}
if (container.ie_exts_present or container.ext) {
procWarning("Not handling extensions");
}
// Create a unique buffer out of transparent container to pass to RRC
rrc_container = srsran::make_byte_buffer();
if (rrc_container == nullptr) {
procError("Fatal Error: Couldn't allocate buffer.");
return srsran::proc_outcome_t::error;
}
memcpy(rrc_container->msg, container.rrc_container.data(), container.rrc_container.size());
rrc_container->N_bytes = container.rrc_container.size();
ho_cmd_msg = &msg;
return srsran::proc_outcome_t::success;
}
void s1ap::ue::ho_prep_proc_t::then(const srsran::proc_state_t& result)
{
if (result.is_error()) {
rrc_interface_s1ap::ho_prep_result ho_prep_result = ue_ptr->ts1_reloc_prep.is_expired()
? rrc_interface_s1ap::ho_prep_result::timeout
: rrc_interface_s1ap::ho_prep_result::failure;
s1ap_ptr->rrc->ho_preparation_complete(ue_ptr->ctxt.rnti, ho_prep_result, *ho_cmd_msg, {});
} else {
s1ap_ptr->rrc->ho_preparation_complete(
ue_ptr->ctxt.rnti, rrc_interface_s1ap::ho_prep_result::success, *ho_cmd_msg, std::move(rrc_container));
procInfo("Completed with success");
}
}
/*********************************************************
* MME Connection
*********************************************************/
srsran::proc_outcome_t s1ap::s1_setup_proc_t::init()
{
procInfo("Starting new MME connection.");
connect_count++;
return start_mme_connection();
}
srsran::proc_outcome_t s1ap::s1_setup_proc_t::start_mme_connection()
{
if (not s1ap_ptr->running) {
procInfo("S1AP is not running anymore.");
return srsran::proc_outcome_t::error;
}
if (s1ap_ptr->mme_connected) {
procInfo("eNB S1AP is already connected to MME");
return srsran::proc_outcome_t::success;
}
auto connect_callback = [this]() {
bool connected = s1ap_ptr->connect_mme();
auto notify_result = [this, connected]() {
s1_setup_proc_t::s1connectresult res;
res.success = connected;
s1ap_ptr->s1setup_proc.trigger(res);
};
s1ap_ptr->task_sched.notify_background_task_result(notify_result);
};
srsran::get_background_workers().push_task(connect_callback);
procDebug("Connection to MME requested.");
return srsran::proc_outcome_t::yield;
}
srsran::proc_outcome_t s1ap::s1_setup_proc_t::react(const srsenb::s1ap::s1_setup_proc_t::s1connectresult& event)
{
if (event.success) {
procInfo("Connected to MME. Sending S1 setup request.");
s1ap_ptr->s1setup_timeout.run();
if (not s1ap_ptr->setup_s1()) {
procError("S1 setup failed. Exiting...");
srsran::console("S1 setup failed\n");
s1ap_ptr->running = false;
return srsran::proc_outcome_t::error;
}
procInfo("S1 setup request sent. Waiting for response.");
return srsran::proc_outcome_t::yield;
}
procInfo("Could not connected to MME. Aborting");
return srsran::proc_outcome_t::error;
}
srsran::proc_outcome_t s1ap::s1_setup_proc_t::react(const srsenb::s1ap::s1_setup_proc_t::s1setupresult& event)
{
if (s1ap_ptr->s1setup_timeout.is_running()) {
s1ap_ptr->s1setup_timeout.stop();
}
if (event.success) {
procInfo("S1Setup procedure completed successfully");
return srsran::proc_outcome_t::success;
}
procError("S1Setup failed.");
srsran::console("S1setup failed\n");
return srsran::proc_outcome_t::error;
}
void s1ap::s1_setup_proc_t::then(const srsran::proc_state_t& result)
{
if (result.is_error()) {
procInfo("Failed to initiate S1 connection. Attempting reconnection in %d seconds",
s1ap_ptr->mme_connect_timer.duration() / 1000);
srsran::console("Failed to initiate S1 connection. Attempting reconnection in %d seconds\n",
s1ap_ptr->mme_connect_timer.duration() / 1000);
s1ap_ptr->rx_socket_handler->remove_socket(s1ap_ptr->mme_socket.get_socket());
s1ap_ptr->mme_socket.close();
procInfo("S1AP socket closed.");
s1ap_ptr->mme_connect_timer.run();
if (s1ap_ptr->args.max_s1_setup_retries > 0 && connect_count > s1ap_ptr->args.max_s1_setup_retries) {
s1ap_ptr->alarms_channel("s1apError");
srsran_terminate("Error connecting to MME");
}
// Try again with in 10 seconds
} else {
connect_count = 0;
}
}
/*********************************************************
* S1AP class
*********************************************************/
s1ap::s1ap(srsran::task_sched_handle task_sched_,
srslog::basic_logger& logger,
srsran::socket_manager_itf* rx_socket_handler_) :
s1setup_proc(this),
logger(logger),
task_sched(task_sched_),
rx_socket_handler(rx_socket_handler_),
alarms_channel(srslog::fetch_log_channel("alarms"))
{
mme_task_queue = task_sched.make_task_queue();
}
int s1ap::init(const s1ap_args_t& args_, rrc_interface_s1ap* rrc_)
{
rrc = rrc_;
args = args_;
build_tai_cgi();
// Setup MME reconnection timer
mme_connect_timer = task_sched.get_unique_timer();
auto mme_connect_run = [this](uint32_t tid) {
if (s1setup_proc.is_busy()) {
logger.error("Failed to initiate S1Setup procedure: procedure is busy.");
}
s1setup_proc.launch();
};
mme_connect_timer.set(args.s1_connect_timer * 1000, mme_connect_run);
// Setup S1Setup timeout
s1setup_timeout = task_sched.get_unique_timer();
uint32_t s1setup_timeout_val = 5000;
s1setup_timeout.set(s1setup_timeout_val, [this](uint32_t tid) {
s1_setup_proc_t::s1setupresult res;
res.success = false;
res.cause = s1_setup_proc_t::s1setupresult::cause_t::timeout;
s1setup_proc.trigger(res);
});
running = true;
// starting MME connection
if (not s1setup_proc.launch()) {
logger.error("Failed to initiate S1Setup procedure: error launching procedure.");
}
return SRSRAN_SUCCESS;
}
void s1ap::stop()
{
running = false;
mme_socket.close();
}
void s1ap::get_metrics(s1ap_metrics_t& m)
{
if (!running) {
m.status = S1AP_ERROR;
return;
}
if (mme_connected) {
m.status = S1AP_READY;
} else {
m.status = S1AP_ATTACHING;
}
}
// Generate common S1AP protocol IEs from config args
void s1ap::build_tai_cgi()
{
uint32_t plmn;
// TAI
s1ap_mccmnc_to_plmn(args.mcc, args.mnc, &plmn);
tai.plm_nid.from_number(plmn);
tai.tac.from_number(args.tac);
// EUTRAN_CGI
eutran_cgi.plm_nid.from_number(plmn);
eutran_cgi.cell_id.from_number((uint32_t)(args.enb_id << 8) | args.cell_id);
}
/*******************************************************************************
/* RRC interface
********************************************************************************/
void s1ap::initial_ue(uint16_t rnti,
uint32_t enb_cc_idx,
asn1::s1ap::rrc_establishment_cause_e cause,
srsran::unique_byte_buffer_t pdu)
{
std::unique_ptr<ue> ue_ptr{new ue{this}};
ue_ptr->ctxt.rnti = rnti;
ue_ptr->ctxt.enb_cc_idx = enb_cc_idx;
ue* u = users.add_user(std::move(ue_ptr));
if (u == nullptr) {
logger.error("Failed to add rnti=0x%x", rnti);
return;
}
u->send_initialuemessage(cause, std::move(pdu), false);
}
void s1ap::initial_ue(uint16_t rnti,
uint32_t enb_cc_idx,
asn1::s1ap::rrc_establishment_cause_e cause,
srsran::unique_byte_buffer_t pdu,
uint32_t m_tmsi,
uint8_t mmec)
{
std::unique_ptr<ue> ue_ptr{new ue{this}};
ue_ptr->ctxt.rnti = rnti;
ue_ptr->ctxt.enb_cc_idx = enb_cc_idx;
ue* u = users.add_user(std::move(ue_ptr));
if (u == nullptr) {
logger.error("Failed to add rnti=0x%x", rnti);
return;
}
u->send_initialuemessage(cause, std::move(pdu), true, m_tmsi, mmec);
}
void s1ap::write_pdu(uint16_t rnti, srsran::unique_byte_buffer_t pdu)
{
logger.info(pdu->msg, pdu->N_bytes, "Received RRC SDU");
ue* u = users.find_ue_rnti(rnti);
if (u == nullptr) {
logger.info("The rnti=0x%x does not exist", rnti);
return;
}
u->send_ulnastransport(std::move(pdu));
}
bool s1ap::user_release(uint16_t rnti, asn1::s1ap::cause_radio_network_e cause_radio)
{
ue* u = users.find_ue_rnti(rnti);
if (u == nullptr) {
logger.warning("Released UE with rnti=0x%x not found", rnti);
rrc->release_ue(rnti);
return false;
}
cause_c cause;
cause.set_radio_network().value = cause_radio.value;
return u->send_uectxtreleaserequest(cause);
}
bool s1ap::user_exists(uint16_t rnti)
{
return users.find_ue_rnti(rnti) != nullptr;
}
void s1ap::user_mod(uint16_t old_rnti, uint16_t new_rnti)
{
logger.info("Modifying user context. Old rnti: 0x%x, new rnti: 0x%x", old_rnti, new_rnti);
if (not user_exists(old_rnti)) {
logger.error("Old rnti does not exist, aborting.");
return;
}
if (user_exists(new_rnti)) {
logger.error("New rnti already exists, aborting.");
return;
}
users.find_ue_rnti(old_rnti)->ctxt.rnti = new_rnti;
}
void s1ap::ue_ctxt_setup_complete(uint16_t rnti)
{
ue* u = users.find_ue_rnti(rnti);
if (u == nullptr) {
return;
}
u->ue_ctxt_setup_complete();
}
void s1ap::notify_rrc_reconf_complete(uint16_t rnti)
{
ue* u = users.find_ue_rnti(rnti);
if (u == nullptr) {
return;
}
u->notify_rrc_reconf_complete();
}
bool s1ap::is_mme_connected()
{
return mme_connected;
}
/*******************************************************************************
/* S1AP connection helpers
********************************************************************************/
bool s1ap::connect_mme()
{
using namespace srsran::net_utils;
logger.info("Connecting to MME %s:%d", args.mme_addr.c_str(), int(MME_PORT));
// Open SCTP socket
if (not mme_socket.open_socket(
srsran::net_utils::addr_family::ipv4, socket_type::seqpacket, srsran::net_utils::protocol_type::SCTP)) {
return false;
}
// Set SO_REUSE_ADDR if necessary
if (args.sctp_reuse_addr) {
if (not mme_socket.reuse_addr()) {
mme_socket.close();
return false;
}
}
// Subscribe to shutdown events
if (not mme_socket.sctp_subscribe_to_events()) {
mme_socket.close();
return false;
}
// Set SRTO_MAX
if (not mme_socket.sctp_set_rto_opts(args.sctp_rto_max)) {
return false;
}
// Set SCTP init options
if (not mme_socket.sctp_set_init_msg_opts(args.sctp_init_max_attempts, args.sctp_max_init_timeo)) {
return false;
}
// Bind socket
if (not mme_socket.bind_addr(args.s1c_bind_addr.c_str(), args.s1c_bind_port)) {
mme_socket.close();
return false;
}
logger.info("SCTP socket opened. fd=%d", mme_socket.fd());
// Connect to the MME address
if (not mme_socket.connect_to(args.mme_addr.c_str(), MME_PORT, &mme_addr)) {
return false;
}
logger.info("SCTP socket connected with MME. fd=%d", mme_socket.fd());
// Assign a handler to rx MME packets
auto rx_callback =
[this](srsran::unique_byte_buffer_t pdu, const sockaddr_in& from, const sctp_sndrcvinfo& sri, int flags) {
// Defer the handling of MME packet to eNB stack main thread
handle_mme_rx_msg(std::move(pdu), from, sri, flags);
};
rx_socket_handler->add_socket_handler(mme_socket.fd(),
srsran::make_sctp_sdu_handler(logger, mme_task_queue, rx_callback));
logger.info("SCTP socket established with MME");
return true;
}
bool s1ap::setup_s1()
{
uint32_t tmp32;
uint16_t tmp16;
uint32_t plmn;
s1ap_mccmnc_to_plmn(args.mcc, args.mnc, &plmn);
plmn = htonl(plmn);
tmp32 = htonl(args.enb_id);
s1ap_pdu_c pdu;
pdu.set_init_msg().load_info_obj(ASN1_S1AP_ID_S1_SETUP);
s1_setup_request_s& container = pdu.init_msg().value.s1_setup_request();
container->global_enb_id.value.plm_nid[0] = ((uint8_t*)&plmn)[1];
container->global_enb_id.value.plm_nid[1] = ((uint8_t*)&plmn)[2];
container->global_enb_id.value.plm_nid[2] = ((uint8_t*)&plmn)[3];
container->global_enb_id.value.enb_id.set_macro_enb_id().from_number(args.enb_id);
container->enbname_present = true;
container->enbname.value.from_string(args.enb_name);
container->supported_tas.value.resize(1);
tmp16 = htons(args.tac);
memcpy(container->supported_tas.value[0].tac.data(), (uint8_t*)&tmp16, 2);
container->supported_tas.value[0].broadcast_plmns.resize(1);
container->supported_tas.value[0].broadcast_plmns[0][0] = ((uint8_t*)&plmn)[1];
container->supported_tas.value[0].broadcast_plmns[0][1] = ((uint8_t*)&plmn)[2];
container->supported_tas.value[0].broadcast_plmns[0][2] = ((uint8_t*)&plmn)[3];
container->default_paging_drx.value.value = asn1::s1ap::paging_drx_opts::v128; // Todo: add to args, config file
return sctp_send_s1ap_pdu(pdu, 0, "s1SetupRequest");
}
/*******************************************************************************
/* S1AP message handlers
********************************************************************************/
bool s1ap::handle_mme_rx_msg(srsran::unique_byte_buffer_t pdu,
const sockaddr_in& from,
const sctp_sndrcvinfo& sri,
int flags)
{
// Handle Notification Case
if (flags & MSG_NOTIFICATION) {
// Received notification
union sctp_notification* notification = (union sctp_notification*)pdu->msg;
logger.info("SCTP Notification %04x", notification->sn_header.sn_type);
bool restart_s1 = false;
if (notification->sn_header.sn_type == SCTP_SHUTDOWN_EVENT) {
logger.info("SCTP Association Shutdown. Association: %d", sri.sinfo_assoc_id);
srsran::console("SCTP Association Shutdown. Association: %d\n", sri.sinfo_assoc_id);
restart_s1 = true;
} else if (notification->sn_header.sn_type == SCTP_PEER_ADDR_CHANGE &&
notification->sn_paddr_change.spc_state == SCTP_ADDR_UNREACHABLE) {
logger.info("SCTP peer addres unreachable. Association: %d", sri.sinfo_assoc_id);
srsran::console("SCTP peer address unreachable. Association: %d\n", sri.sinfo_assoc_id);
restart_s1 = true;
} else if (notification->sn_header.sn_type == SCTP_REMOTE_ERROR) {
logger.info("SCTP remote error. Association: %d", sri.sinfo_assoc_id);
srsran::console("SCTP remote error. Association: %d\n", sri.sinfo_assoc_id);
restart_s1 = true;
} else if (notification->sn_header.sn_type == SCTP_ASSOC_CHANGE) {
logger.info("SCTP association changed. Association: %d", sri.sinfo_assoc_id);
srsran::console("SCTP association changed. Association: %d\n", sri.sinfo_assoc_id);
}
if (restart_s1) {
logger.info("Restarting S1 connection");
srsran::console("Restarting S1 connection\n");
rx_socket_handler->remove_socket(mme_socket.get_socket());
mme_socket.close();
while (users.size() != 0) {
std::unordered_map<uint32_t, std::unique_ptr<ue> >::iterator it = users.begin();
uint16_t rnti = it->second->ctxt.rnti;
rrc->release_erabs(rnti);
rrc->release_ue(rnti);
users.erase(it->second.get());
}
}
} else if (pdu->N_bytes == 0) {
logger.error("SCTP return 0 bytes. Closing socket");
mme_socket.close();
}
// Restart MME connection procedure if we lost connection
if (not mme_socket.is_open()) {
mme_connected = false;
if (s1setup_proc.is_busy()) {
logger.error("Failed to initiate MME connection procedure, as it is already running.");
return false;
}
s1setup_proc.launch();
return false;
}
if ((flags & MSG_NOTIFICATION) == 0 && pdu->N_bytes != 0) {
handle_s1ap_rx_pdu(pdu.get());
}
return true;
}
bool s1ap::handle_s1ap_rx_pdu(srsran::byte_buffer_t* pdu)
{
// Save message to PCAP
if (pcap != nullptr) {
pcap->write_s1ap(pdu->msg, pdu->N_bytes);
}
s1ap_pdu_c rx_pdu;
asn1::cbit_ref bref(pdu->msg, pdu->N_bytes);
if (rx_pdu.unpack(bref) != asn1::SRSASN_SUCCESS) {
logger.error(pdu->msg, pdu->N_bytes, "Failed to unpack received PDU");
cause_c cause;
cause.set_protocol().value = cause_protocol_opts::transfer_syntax_error;
send_error_indication(cause);
return false;
}
log_s1ap_msg(rx_pdu, srsran::make_span(*pdu), true);
switch (rx_pdu.type().value) {
case s1ap_pdu_c::types_opts::init_msg:
return handle_initiatingmessage(rx_pdu.init_msg());
case s1ap_pdu_c::types_opts::successful_outcome:
return handle_successfuloutcome(rx_pdu.successful_outcome());
case s1ap_pdu_c::types_opts::unsuccessful_outcome:
return handle_unsuccessfuloutcome(rx_pdu.unsuccessful_outcome());
default:
logger.error("Unhandled PDU type %d", rx_pdu.type().value);
return false;
}
return true;
}
bool s1ap::handle_initiatingmessage(const init_msg_s& msg)
{
switch (msg.value.type().value) {
case s1ap_elem_procs_o::init_msg_c::types_opts::dl_nas_transport:
return handle_dlnastransport(msg.value.dl_nas_transport());
case s1ap_elem_procs_o::init_msg_c::types_opts::init_context_setup_request:
return handle_initialctxtsetuprequest(msg.value.init_context_setup_request());
case s1ap_elem_procs_o::init_msg_c::types_opts::ue_context_release_cmd:
return handle_uectxtreleasecommand(msg.value.ue_context_release_cmd());
case s1ap_elem_procs_o::init_msg_c::types_opts::paging:
return handle_paging(msg.value.paging());
case s1ap_elem_procs_o::init_msg_c::types_opts::erab_setup_request:
return handle_erabsetuprequest(msg.value.erab_setup_request());
case s1ap_elem_procs_o::init_msg_c::types_opts::erab_release_cmd:
return handle_erabreleasecommand(msg.value.erab_release_cmd());
case s1ap_elem_procs_o::init_msg_c::types_opts::erab_modify_request:
return handle_erabmodifyrequest(msg.value.erab_modify_request());
case s1ap_elem_procs_o::init_msg_c::types_opts::ue_context_mod_request:
return handle_uecontextmodifyrequest(msg.value.ue_context_mod_request());
case s1ap_elem_procs_o::init_msg_c::types_opts::ho_request:
return handle_handover_request(msg.value.ho_request());
case s1ap_elem_procs_o::init_msg_c::types_opts::mme_status_transfer:
return handle_mme_status_transfer(msg.value.mme_status_transfer());
default:
logger.error("Unhandled initiating message: %s", msg.value.type().to_string());
}
return true;
}
bool s1ap::handle_successfuloutcome(const successful_outcome_s& msg)
{
switch (msg.value.type().value) {
case s1ap_elem_procs_o::successful_outcome_c::types_opts::s1_setup_resp:
return handle_s1setupresponse(msg.value.s1_setup_resp());
case s1ap_elem_procs_o::successful_outcome_c::types_opts::ho_cmd:
return handle_handover_command(msg.value.ho_cmd());
case s1ap_elem_procs_o::successful_outcome_c::types_opts::ho_cancel_ack:
return true;
default:
logger.error("Unhandled successful outcome message: %s", msg.value.type().to_string());
}
return true;
}
bool s1ap::handle_unsuccessfuloutcome(const unsuccessful_outcome_s& msg)
{
switch (msg.value.type().value) {
case s1ap_elem_procs_o::unsuccessful_outcome_c::types_opts::s1_setup_fail:
return handle_s1setupfailure(msg.value.s1_setup_fail());
case s1ap_elem_procs_o::unsuccessful_outcome_c::types_opts::ho_prep_fail:
return handle_handover_preparation_failure(msg.value.ho_prep_fail());
default:
logger.error("Unhandled unsuccessful outcome message: %s", msg.value.type().to_string());
}
return true;
}
bool s1ap::handle_s1setupresponse(const asn1::s1ap::s1_setup_resp_s& msg)
{
if (s1setup_proc.is_idle()) {
asn1::s1ap::cause_c cause;
cause.set_protocol().value = cause_protocol_opts::msg_not_compatible_with_receiver_state;
send_error_indication(cause);
return false;
}
s1setupresponse = msg;
mme_connected = true;
s1_setup_proc_t::s1setupresult res;
res.success = true;
s1setup_proc.trigger(res);
return true;
}
bool s1ap::handle_dlnastransport(const dl_nas_transport_s& msg)
{
if (msg.ext) {
logger.warning("Not handling S1AP message extension");
}
ue* u = handle_s1apmsg_ue_id(msg->enb_ue_s1ap_id.value.value, msg->mme_ue_s1ap_id.value.value);
if (u == nullptr) {
return false;
}
if (msg->ho_restrict_list_present) {
logger.warning("Not handling HandoverRestrictionList");
}
if (msg->subscriber_profile_idfor_rfp_present) {
logger.warning("Not handling SubscriberProfileIDforRFP");
}
srsran::unique_byte_buffer_t pdu = srsran::make_byte_buffer();
if (pdu == nullptr) {
logger.error("Fatal Error: Couldn't allocate buffer in s1ap::run_thread().");
return false;
}
memcpy(pdu->msg, msg->nas_pdu.value.data(), msg->nas_pdu.value.size());
pdu->N_bytes = msg->nas_pdu.value.size();
rrc->write_dl_info(u->ctxt.rnti, std::move(pdu));
return true;
}
bool s1ap::handle_initialctxtsetuprequest(const init_context_setup_request_s& msg)
{
WarnUnsupportFeature(msg.ext, "message extension");
WarnUnsupportFeature(msg->add_cs_fallback_ind_present, "AdditionalCSFallbackIndicator");
WarnUnsupportFeature(msg->csg_membership_status_present, "CSGMembershipStatus");
WarnUnsupportFeature(msg->gummei_id_present, "GUMMEI_ID");
WarnUnsupportFeature(msg->ho_restrict_list_present, "HandoverRestrictionList");
WarnUnsupportFeature(msg->management_based_mdt_allowed_present, "ManagementBasedMDTAllowed");
WarnUnsupportFeature(msg->management_based_mdtplmn_list_present, "ManagementBasedMDTPLMNList");
WarnUnsupportFeature(msg->mme_ue_s1ap_id_minus2_present, "MME_UE_S1AP_ID_2");
WarnUnsupportFeature(msg->registered_lai_present, "RegisteredLAI");
WarnUnsupportFeature(msg->srvcc_operation_possible_present, "SRVCCOperationPossible");
WarnUnsupportFeature(msg->subscriber_profile_idfor_rfp_present, "SubscriberProfileIDforRFP");
WarnUnsupportFeature(msg->trace_activation_present, "TraceActivation");
WarnUnsupportFeature(msg->ue_radio_cap_present, "UERadioCapability");
ue* u = handle_s1apmsg_ue_id(msg->enb_ue_s1ap_id.value.value, msg->mme_ue_s1ap_id.value.value);
if (u == nullptr) {
return false;
}
if (u->get_state() == s1ap_proc_id_t::init_context_setup_request) {
logger.warning("Initial Context Setup Request already in progress. Ignoring ICS request.");
asn1::s1ap::cause_c cause;
cause.set_protocol().value = cause_protocol_opts::msg_not_compatible_with_receiver_state;
send_error_indication(cause, msg->enb_ue_s1ap_id.value.value, msg->mme_ue_s1ap_id.value.value);
return false;
}
// Setup UE ctxt in RRC
if (not rrc->setup_ue_ctxt(u->ctxt.rnti, msg)) {
return false;
}
// Update E-RABs
erab_id_list updated_erabs;
erab_item_list failed_cfg_erabs;
add_repeated_erab_ids(msg->erab_to_be_setup_list_ctxt_su_req.value, failed_cfg_erabs);
for (const auto& item : msg->erab_to_be_setup_list_ctxt_su_req.value) {
const auto& erab = item->erab_to_be_setup_item_ctxt_su_req();
if (contains_erab_id(failed_cfg_erabs, erab.erab_id)) {
// E-RAB is duplicate
continue;
}
WarnUnsupportFeature(erab.ext, "E-RABToBeSetupListBearerSUReq extensions");
WarnUnsupportFeature(erab.ie_exts_present, "E-RABToBeSetupListBearerSUReq extensions");
if (erab.transport_layer_address.length() > 32) {
logger.error("IPv6 addresses not currently supported");
failed_cfg_erabs.push_back(erab_item_s());
failed_cfg_erabs.back().erab_id = erab.erab_id;
failed_cfg_erabs.back().cause.set_radio_network().value = cause_radio_network_opts::invalid_qos_combination;
continue;
}
cause_c cause;
if (rrc->setup_erab(u->ctxt.rnti,
erab.erab_id,
erab.erab_level_qos_params,
erab.nas_pdu,
erab.transport_layer_address,
erab.gtp_teid.to_number(),
cause) == SRSRAN_SUCCESS) {
updated_erabs.push_back(erab.erab_id);
} else {
failed_cfg_erabs.push_back(erab_item_s());
failed_cfg_erabs.back().erab_id = erab.erab_id;
failed_cfg_erabs.back().cause = cause;
}
}
/* Ideally the check below would be "if (users[rnti].is_csfb)" */
if (msg->cs_fallback_ind_present) {
if (msg->cs_fallback_ind.value.value == cs_fallback_ind_opts::cs_fallback_required ||
msg->cs_fallback_ind.value.value == cs_fallback_ind_opts::cs_fallback_high_prio) {
// Send RRC Release (cs-fallback-triggered) to MME
cause_c cause;
cause.set_radio_network().value = cause_radio_network_opts::cs_fallback_triggered;
/* TODO: This should normally probably only be sent after the SecurityMode procedure has completed! */
u->send_uectxtreleaserequest(cause);
}
}
// E-RAB Setup Response is sent after the security cfg is complete
// Note: No need to notify RRC to send RRC Reconfiguration
sanitize_response_erab_lists(failed_cfg_erabs, updated_erabs);
u->set_state(s1ap_proc_id_t::init_context_setup_request, updated_erabs, failed_cfg_erabs);
return true;
}
bool s1ap::handle_paging(const asn1::s1ap::paging_s& msg)
{
WarnUnsupportFeature(msg.ext, "S1AP message extension");
uint32_t ueid = msg->ue_id_idx_value.value.to_number();
rrc->add_paging_id(ueid, msg->ue_paging_id.value);
return true;
}
bool s1ap::handle_erabsetuprequest(const erab_setup_request_s& msg)
{
WarnUnsupportFeature(msg.ext, "S1AP message extension");
ue* u = handle_s1apmsg_ue_id(msg->enb_ue_s1ap_id.value.value, msg->mme_ue_s1ap_id.value.value);
if (u == nullptr) {
return false;
}
if (msg->ueaggregate_maximum_bitrate_present) {
rrc->set_aggregate_max_bitrate(u->ctxt.rnti, msg->ueaggregate_maximum_bitrate.value);
}
erab_id_list updated_erabs;
erab_item_list failed_cfg_erabs;
add_repeated_erab_ids(msg->erab_to_be_setup_list_bearer_su_req.value, failed_cfg_erabs);
for (const auto& item : msg->erab_to_be_setup_list_bearer_su_req.value) {
const auto& erab = item->erab_to_be_setup_item_bearer_su_req();
if (contains_erab_id(failed_cfg_erabs, erab.erab_id)) {
// E-RAB is duplicate
continue;
}
WarnUnsupportFeature(erab.ext, "E-RABToBeSetupListBearerSUReq extensions");
WarnUnsupportFeature(erab.ie_exts_present, "E-RABToBeSetupListBearerSUReq extensions");
if (erab.transport_layer_address.length() > 32) {
logger.error("IPv6 addresses not currently supported");
failed_cfg_erabs.push_back(erab_item_s());
failed_cfg_erabs.back().erab_id = erab.erab_id;
failed_cfg_erabs.back().cause.set_radio_network().value = cause_radio_network_opts::invalid_qos_combination;
continue;
}
cause_c cause;
if (rrc->setup_erab(u->ctxt.rnti,
erab.erab_id,
erab.erab_level_qos_params,
erab.nas_pdu,
erab.transport_layer_address,
erab.gtp_teid.to_number(),
cause) == SRSRAN_SUCCESS) {
updated_erabs.push_back(erab.erab_id);
} else {
failed_cfg_erabs.push_back(erab_item_s());
failed_cfg_erabs.back().erab_id = erab.erab_id;
failed_cfg_erabs.back().cause = cause;
}
}
// Notify UE of updates
if (not updated_erabs.empty()) {
rrc->notify_ue_erab_updates(u->ctxt.rnti, {});
}
sanitize_response_erab_lists(failed_cfg_erabs, updated_erabs);
return u->send_erab_setup_response(updated_erabs, failed_cfg_erabs);
}
bool s1ap::handle_erabmodifyrequest(const erab_modify_request_s& msg)
{
WarnUnsupportFeature(msg.ext, "S1AP message extension");
ue* u = handle_s1apmsg_ue_id(msg->enb_ue_s1ap_id.value.value, msg->mme_ue_s1ap_id.value.value);
if (u == nullptr) {
return false;
}
if (msg->ueaggregate_maximum_bitrate_present) {
rrc->set_aggregate_max_bitrate(u->ctxt.rnti, msg->ueaggregate_maximum_bitrate.value);
}
erab_id_list updated_erabs;
erab_item_list failed_cfg_erabs;
add_repeated_erab_ids(msg->erab_to_be_modified_list_bearer_mod_req.value, failed_cfg_erabs);
for (const auto& item : msg->erab_to_be_modified_list_bearer_mod_req.value) {
const auto& erab = item->erab_to_be_modified_item_bearer_mod_req();
if (contains_erab_id(failed_cfg_erabs, erab.erab_id)) {
// E-RAB is duplicate
continue;
}
WarnUnsupportFeature(erab.ext, "E-RABToBeSetupListBearerSUReq extensions");
WarnUnsupportFeature(erab.ie_exts_present, "E-RABToBeSetupListBearerSUReq extensions");
cause_c cause;
if (rrc->modify_erab(u->ctxt.rnti, erab.erab_id, erab.erab_level_qos_params, erab.nas_pdu, cause) ==
SRSRAN_SUCCESS) {
updated_erabs.push_back(erab.erab_id);
} else {
failed_cfg_erabs.push_back(erab_item_s());
failed_cfg_erabs.back().erab_id = erab.erab_id;
failed_cfg_erabs.back().cause = cause;
}
}
// Notify UE of updates
if (not updated_erabs.empty()) {
rrc->notify_ue_erab_updates(u->ctxt.rnti, {});
}
// send E-RAB modify response back to the mme
sanitize_response_erab_lists(failed_cfg_erabs, updated_erabs);
return u->send_erab_modify_response(updated_erabs, failed_cfg_erabs);
}
/**
* @brief eNB handles MME's message "E-RAB RELEASE COMMAND"
* @remark TS 36.413, Section 8.2.3.2 - E-RAB Release - MME initiated (successful operation)
* @param erabs_successfully_released
* @param erabs_failed_to_release
* @return true if message was sent
*/
bool s1ap::handle_erabreleasecommand(const erab_release_cmd_s& msg)
{
WarnUnsupportFeature(msg.ext, "S1AP message extension");
ue* u = handle_s1apmsg_ue_id(msg->enb_ue_s1ap_id.value.value, msg->mme_ue_s1ap_id.value.value);
if (u == nullptr) {
return false;
}
erab_id_list updated_erabs;
erab_item_list failed_cfg_erabs;
auto is_repeated_erab_id = [&updated_erabs, &failed_cfg_erabs](uint8_t erab_id) {
return (std::count(updated_erabs.begin(), updated_erabs.end(), erab_id) > 0) or
(std::any_of(failed_cfg_erabs.begin(), failed_cfg_erabs.end(), [erab_id](const erab_item_s& e) {
return e.erab_id == erab_id;
}));
};
for (const auto& item : msg->erab_to_be_released_list.value) {
const auto& erab = item->erab_item();
if (is_repeated_erab_id(erab.erab_id)) {
// TS 36.413, 8.2.3.3 - ignore the duplication of E-RAB ID IEs
continue;
}
if (rrc->release_erab(u->ctxt.rnti, erab.erab_id) == SRSRAN_SUCCESS) {
updated_erabs.push_back(erab.erab_id);
} else {
failed_cfg_erabs.push_back(erab_item_s());
failed_cfg_erabs.back().erab_id = erab.erab_id;
failed_cfg_erabs.back().cause.set_radio_network().value = cause_radio_network_opts::unknown_erab_id;
}
}
// Notify RRC of E-RAB update. (RRC reconf message is going to be sent.
if (not updated_erabs.empty()) {
rrc->notify_ue_erab_updates(u->ctxt.rnti, msg->nas_pdu.value);
}
// Send E-RAB release response back to the MME
sanitize_response_erab_lists(failed_cfg_erabs, updated_erabs);
if (not u->send_erab_release_response(updated_erabs, failed_cfg_erabs)) {
logger.info("Failed to send ERABReleaseResponse");
return false;
}
return true;
}
bool s1ap::handle_uecontextmodifyrequest(const ue_context_mod_request_s& msg)
{
WarnUnsupportFeature(msg.ext, "S1AP message extension");
WarnUnsupportFeature(msg->add_cs_fallback_ind_present, "AdditionalCSFallbackIndicator");
WarnUnsupportFeature(msg->csg_membership_status_present, "CSGMembershipStatus");
WarnUnsupportFeature(msg->registered_lai_present, "RegisteredLAI");
WarnUnsupportFeature(msg->subscriber_profile_idfor_rfp_present, "SubscriberProfileIDforRFP");
ue* u = handle_s1apmsg_ue_id(msg->enb_ue_s1ap_id.value.value, msg->mme_ue_s1ap_id.value.value);
if (u == nullptr) {
return false;
}
if (!rrc->modify_ue_ctxt(u->ctxt.rnti, msg)) {
cause_c cause;
cause.set_misc().value = cause_misc_opts::unspecified;
u->send_uectxtmodifyfailure(cause);
return true;
}
// Send UEContextModificationResponse
u->send_uectxtmodifyresp();
/* Ideally the check below would be "if (users[rnti].is_csfb)" */
if (msg->cs_fallback_ind_present) {
if (msg->cs_fallback_ind.value.value == cs_fallback_ind_opts::cs_fallback_required ||
msg->cs_fallback_ind.value.value == cs_fallback_ind_opts::cs_fallback_high_prio) {
// Send RRC Release (cs-fallback-triggered) to MME
cause_c cause;
cause.set_radio_network().value = cause_radio_network_opts::cs_fallback_triggered;
u->send_uectxtreleaserequest(cause);
}
}
return true;
}
bool s1ap::handle_uectxtreleasecommand(const ue_context_release_cmd_s& msg)
{
WarnUnsupportFeature(msg.ext, "S1AP message extension");
ue* u = nullptr;
if (msg->ue_s1ap_ids.value.type().value == ue_s1ap_ids_c::types_opts::ue_s1ap_id_pair) {
const auto& idpair = msg->ue_s1ap_ids.value.ue_s1ap_id_pair();
if (idpair.ext) {
logger.warning("Not handling S1AP message extension");
}
if (idpair.ie_exts_present) {
logger.warning("Not handling S1AP message iE_Extensions");
}
u = handle_s1apmsg_ue_id(idpair.enb_ue_s1ap_id, idpair.mme_ue_s1ap_id);
if (u == nullptr) {
return false;
}
} else {
uint32_t mme_ue_id = msg->ue_s1ap_ids.value.mme_ue_s1ap_id();
u = users.find_ue_mmeid(mme_ue_id);
if (u == nullptr) {
logger.warning("UE for mme_ue_s1ap_id:%d not found - discarding message", mme_ue_id);
return false;
}
}
uint16_t rnti = u->ctxt.rnti;
rrc->release_erabs(rnti);
u->send_uectxtreleasecomplete();
users.erase(u);
logger.info("UE context for RNTI:0x%x released", rnti);
rrc->release_ue(rnti);
return true;
}
bool s1ap::handle_s1setupfailure(const asn1::s1ap::s1_setup_fail_s& msg)
{
if (s1setup_proc.is_idle()) {
asn1::s1ap::cause_c cause;
cause.set_protocol().value = cause_protocol_opts::msg_not_compatible_with_receiver_state;
send_error_indication(cause);
return false;
}
s1_setup_proc_t::s1setupresult res;
res.success = false;
s1setup_proc.trigger(res);
std::string cause = get_cause(msg->cause.value);
logger.error("S1 Setup Failure. Cause: %s", cause.c_str());
srsran::console("S1 Setup Failure. Cause: %s\n", cause.c_str());
return true;
}
bool s1ap::handle_handover_preparation_failure(const ho_prep_fail_s& msg)
{
ue* u = handle_s1apmsg_ue_id(msg->enb_ue_s1ap_id.value.value, msg->mme_ue_s1ap_id.value.value);
if (u == nullptr) {
return false;
}
if (u->ho_prep_proc.is_idle()) {
asn1::s1ap::cause_c cause;
cause.set_protocol().value = cause_protocol_opts::msg_not_compatible_with_receiver_state;
send_error_indication(cause);
return false;
}
u->ho_prep_proc.trigger(msg);
return true;
}
bool s1ap::handle_handover_command(const asn1::s1ap::ho_cmd_s& msg)
{
ue* u = handle_s1apmsg_ue_id(msg->enb_ue_s1ap_id.value.value, msg->mme_ue_s1ap_id.value.value);
if (u == nullptr) {
return false;
}
if (u->ho_prep_proc.is_idle()) {
asn1::s1ap::cause_c cause;
cause.set_protocol().value = cause_protocol_opts::msg_not_compatible_with_receiver_state;
send_error_indication(cause);
return false;
}
u->ho_prep_proc.trigger(msg);
return true;
}
/**************************************************************
* TS 36.413 - Section 8.4.2 - "Handover Resource Allocation"
*************************************************************/
bool s1ap::handle_handover_request(const asn1::s1ap::ho_request_s& msg)
{
uint16_t rnti = SRSRAN_INVALID_RNTI;
uint32_t mme_ue_s1ap_id = msg->mme_ue_s1ap_id.value.value;
asn1::s1ap::cause_c cause;
cause.set_misc().value = cause_misc_opts::unspecified;
if (msg.ext or msg->ho_restrict_list_present) {
logger.warning("Not handling S1AP Handover Request extensions or Handover Restriction List");
}
if (msg->handov_type.value.value != handov_type_opts::intralte) {
logger.error("Not handling S1AP non-intra LTE handovers");
cause.set_radio_network().value = cause_radio_network_opts::interrat_redirection;
send_ho_failure(mme_ue_s1ap_id, cause);
return false;
}
// Confirm the UE does not exist in TeNB
if (users.find_ue_mmeid(msg->mme_ue_s1ap_id.value.value) != nullptr) {
logger.error("The provided MME_UE_S1AP_ID=%" PRIu64 " is already connected to the cell",
msg->mme_ue_s1ap_id.value.value);
cause.set_radio_network().value = cause_radio_network_opts::unknown_mme_ue_s1ap_id;
send_ho_failure(mme_ue_s1ap_id, cause);
return false;
}
// Create user ctxt object and associated MME context
std::unique_ptr<ue> ue_ptr{new ue{this}};
ue_ptr->ctxt.mme_ue_s1ap_id = msg->mme_ue_s1ap_id.value.value;
srsran_assert(users.add_user(std::move(ue_ptr)) != nullptr, "Unexpected failure to create S1AP UE");
// Unpack Transparent Container
sourceenb_to_targetenb_transparent_container_s container;
asn1::cbit_ref bref{msg->source_to_target_transparent_container.value.data(),
msg->source_to_target_transparent_container.value.size()};
if (container.unpack(bref) != asn1::SRSASN_SUCCESS) {
logger.warning("Failed to unpack SourceToTargetTransparentContainer");
cause.set_protocol().value = cause_protocol_opts::transfer_syntax_error;
send_ho_failure(mme_ue_s1ap_id, cause);
return false;
}
// Handle Handover Resource Allocation
rnti = rrc->start_ho_ue_resource_alloc(msg, container, cause);
if (rnti == SRSRAN_INVALID_RNTI) {
send_ho_failure(mme_ue_s1ap_id, cause);
return false;
}
return true;
}
void s1ap::send_ho_failure(uint32_t mme_ue_s1ap_id, const asn1::s1ap::cause_c& cause)
{
// Remove created s1ap user
ue* u = users.find_ue_mmeid(mme_ue_s1ap_id);
if (u != nullptr) {
users.erase(u);
}
s1ap_pdu_c tx_pdu;
tx_pdu.set_unsuccessful_outcome().load_info_obj(ASN1_S1AP_ID_HO_RES_ALLOC);
ho_fail_s& container = tx_pdu.unsuccessful_outcome().value.ho_fail();
container->mme_ue_s1ap_id.value = mme_ue_s1ap_id;
container->cause.value = cause;
sctp_send_s1ap_pdu(tx_pdu, SRSRAN_INVALID_RNTI, "HandoverFailure");
}
bool s1ap::send_ho_req_ack(const asn1::s1ap::ho_request_s& msg,
uint16_t rnti,
uint32_t enb_cc_idx,
srsran::unique_byte_buffer_t ho_cmd,
srsran::span<asn1::s1ap::erab_admitted_item_s> admitted_bearers,
srsran::const_span<asn1::s1ap::erab_item_s> not_admitted_bearers)
{
s1ap_pdu_c tx_pdu;
tx_pdu.set_successful_outcome().load_info_obj(ASN1_S1AP_ID_HO_RES_ALLOC);
ho_request_ack_s& container = tx_pdu.successful_outcome().value.ho_request_ack();
ue* ue_ptr = users.find_ue_mmeid(msg->mme_ue_s1ap_id.value.value);
if (ue_ptr == nullptr) {
logger.error("The MME-S1AP-UE-ID=%ld is not valid", msg->mme_ue_s1ap_id.value.value);
return false;
}
ue_ptr->ctxt.rnti = rnti;
ue_ptr->ctxt.enb_cc_idx = enb_cc_idx;
container->mme_ue_s1ap_id.value = msg->mme_ue_s1ap_id.value.value;
container->enb_ue_s1ap_id.value = ue_ptr->ctxt.enb_ue_s1ap_id;
// Add admitted E-RABs
container->erab_admitted_list.value.resize(admitted_bearers.size());
for (size_t i = 0; i < admitted_bearers.size(); ++i) {
container->erab_admitted_list.value[i].load_info_obj(ASN1_S1AP_ID_ERAB_ADMITTED_ITEM);
auto& c = container->erab_admitted_list.value[i]->erab_admitted_item();
c = admitted_bearers[i];
if (!args.gtp_advertise_addr.empty()) {
c.transport_layer_address = addr_to_asn1(args.gtp_advertise_addr.c_str());
} else {
c.transport_layer_address = addr_to_asn1(args.gtp_bind_addr.c_str());
}
// If E-RAB is proposed for forward tunneling
if (c.dl_g_tp_teid_present) {
c.dl_transport_layer_address_present = true;
c.dl_transport_layer_address = c.transport_layer_address;
}
if (c.ul_gtp_teid_present) {
c.ul_transport_layer_address_present = true;
c.ul_transport_layer_address = c.transport_layer_address;
}
}
// Add failed to Setup E-RABs
if (not not_admitted_bearers.empty()) {
container->erab_failed_to_setup_list_ho_req_ack_present = true;
container->erab_failed_to_setup_list_ho_req_ack.value.resize(not_admitted_bearers.size());
for (size_t i = 0; i < not_admitted_bearers.size(); ++i) {
container->erab_failed_to_setup_list_ho_req_ack.value[i].load_info_obj(
ASN1_S1AP_ID_ERAB_FAILEDTO_SETUP_ITEM_HO_REQ_ACK);
auto& erab = container->erab_failed_to_setup_list_ho_req_ack.value[i]->erab_failedto_setup_item_ho_req_ack();
erab.erab_id = not_admitted_bearers[i].erab_id;
erab.cause = not_admitted_bearers[i].cause;
}
}
// Pack transparent container
asn1::s1ap::targetenb_to_sourceenb_transparent_container_s transparent_container;
transparent_container.rrc_container.resize(ho_cmd->N_bytes);
memcpy(transparent_container.rrc_container.data(), ho_cmd->msg, ho_cmd->N_bytes);
auto& pdu = ho_cmd; // reuse pdu
asn1::bit_ref bref{pdu->msg, pdu->get_tailroom()};
if (transparent_container.pack(bref) != asn1::SRSASN_SUCCESS) {
logger.error("Failed to pack TargeteNBToSourceeNBTransparentContainer");
return false;
}
container->target_to_source_transparent_container.value.resize(bref.distance_bytes());
memcpy(container->target_to_source_transparent_container.value.data(), pdu->msg, bref.distance_bytes());
return sctp_send_s1ap_pdu(tx_pdu, rnti, "HandoverRequestAcknowledge");
}
bool s1ap::handle_mme_status_transfer(const asn1::s1ap::mme_status_transfer_s& msg)
{
ue* u = handle_s1apmsg_ue_id(msg->enb_ue_s1ap_id.value.value, msg->mme_ue_s1ap_id.value.value);
if (u == nullptr) {
return false;
}
rrc->set_erab_status(u->ctxt.rnti,
msg->enb_status_transfer_transparent_container.value.bearers_subject_to_status_transfer_list);
return true;
}
void s1ap::send_ho_notify(uint16_t rnti, uint64_t target_eci)
{
ue* user_ptr = users.find_ue_rnti(rnti);
if (user_ptr == nullptr) {
return;
}
s1ap_pdu_c tx_pdu;
tx_pdu.set_init_msg().load_info_obj(ASN1_S1AP_ID_HO_NOTIF);
ho_notify_s& container = tx_pdu.init_msg().value.ho_notify();
container->mme_ue_s1ap_id.value = user_ptr->ctxt.mme_ue_s1ap_id.value();
container->enb_ue_s1ap_id.value = user_ptr->ctxt.enb_ue_s1ap_id;
container->eutran_cgi.value = eutran_cgi;
container->eutran_cgi.value.cell_id.from_number(target_eci);
container->tai.value = tai;
sctp_send_s1ap_pdu(tx_pdu, rnti, "HandoverNotify");
}
void s1ap::send_ho_cancel(uint16_t rnti, const asn1::s1ap::cause_c& cause)
{
ue* user_ptr = users.find_ue_rnti(rnti);
if (user_ptr == nullptr) {
logger.warning("Canceling handover for non-existent rnti=0x%x", rnti);
return;
}
user_ptr->send_ho_cancel(cause);
}
bool s1ap::release_erabs(uint16_t rnti, const std::vector<uint16_t>& erabs_successfully_released)
{
ue* user_ptr = users.find_ue_rnti(rnti);
if (user_ptr == nullptr) {
return false;
}
return user_ptr->send_erab_release_indication(erabs_successfully_released);
}
bool s1ap::send_ue_cap_info_indication(uint16_t rnti, srsran::unique_byte_buffer_t ue_radio_cap)
{
ue* user_ptr = users.find_ue_rnti(rnti);
if (user_ptr == nullptr) {
return false;
}
return user_ptr->send_ue_cap_info_indication(std::move(ue_radio_cap));
}
bool s1ap::send_error_indication(const asn1::s1ap::cause_c& cause,
srsran::optional<uint32_t> enb_ue_s1ap_id,
srsran::optional<uint32_t> mme_ue_s1ap_id)
{
if (not mme_connected) {
return false;
}
s1ap_pdu_c tx_pdu;
tx_pdu.set_init_msg().load_info_obj(ASN1_S1AP_ID_ERROR_IND);
auto& container = tx_pdu.init_msg().value.error_ind();
uint16_t rnti = SRSRAN_INVALID_RNTI;
container->enb_ue_s1ap_id_present = enb_ue_s1ap_id.has_value();
if (enb_ue_s1ap_id.has_value()) {
container->enb_ue_s1ap_id.value = enb_ue_s1ap_id.value();
ue* user_ptr = users.find_ue_enbid(enb_ue_s1ap_id.value());
rnti = user_ptr != nullptr ? user_ptr->ctxt.rnti : SRSRAN_INVALID_RNTI;
}
container->mme_ue_s1ap_id_present = mme_ue_s1ap_id.has_value();
if (mme_ue_s1ap_id.has_value()) {
container->mme_ue_s1ap_id.value = mme_ue_s1ap_id.value();
}
container->s_tmsi_present = false;
container->cause_present = true;
container->cause.value = cause;
return sctp_send_s1ap_pdu(tx_pdu, rnti, "Error Indication");
}
/*******************************************************************************
/* S1AP message senders
********************************************************************************/
bool s1ap::ue::send_initialuemessage(asn1::s1ap::rrc_establishment_cause_e cause,
srsran::unique_byte_buffer_t pdu,
bool has_tmsi,
uint32_t m_tmsi,
uint8_t mmec)
{
if (not s1ap_ptr->mme_connected) {
return false;
}
s1ap_pdu_c tx_pdu;
tx_pdu.set_init_msg().load_info_obj(ASN1_S1AP_ID_INIT_UE_MSG);
init_ue_msg_s& container = tx_pdu.init_msg().value.init_ue_msg();
// S_TMSI
if (has_tmsi) {
container->s_tmsi_present = true;
uint32_to_uint8(m_tmsi, container->s_tmsi.value.m_tmsi.data());
container->s_tmsi.value.mmec[0] = mmec;
}
// ENB_UE_S1AP_ID
container->enb_ue_s1ap_id.value = ctxt.enb_ue_s1ap_id;
// NAS_PDU
container->nas_pdu.value.resize(pdu->N_bytes);
memcpy(container->nas_pdu.value.data(), pdu->msg, pdu->N_bytes);
// TAI
container->tai.value = s1ap_ptr->tai;
// EUTRAN_CGI
container->eutran_cgi.value = s1ap_ptr->eutran_cgi;
// RRC Establishment Cause
container->rrc_establishment_cause.value = cause;
return s1ap_ptr->sctp_send_s1ap_pdu(tx_pdu, ctxt.rnti, "InitialUEMessage");
}
bool s1ap::ue::send_ulnastransport(srsran::unique_byte_buffer_t pdu)
{
if (not ctxt.mme_ue_s1ap_id.has_value()) {
logger.error("Trying to send UL NAS Transport message for rnti=0x%x without MME-S1AP-UE-ID", ctxt.rnti);
return false;
}
s1ap_pdu_c tx_pdu;
tx_pdu.set_init_msg().load_info_obj(ASN1_S1AP_ID_UL_NAS_TRANSPORT);
ul_nas_transport_s& container = tx_pdu.init_msg().value.ul_nas_transport();
container->mme_ue_s1ap_id.value = ctxt.mme_ue_s1ap_id.value();
container->enb_ue_s1ap_id.value = ctxt.enb_ue_s1ap_id;
// NAS PDU
container->nas_pdu.value.resize(pdu->N_bytes);
memcpy(container->nas_pdu.value.data(), pdu->msg, pdu->N_bytes);
// EUTRAN CGI
container->eutran_cgi.value = s1ap_ptr->eutran_cgi;
// TAI
container->tai.value = s1ap_ptr->tai;
return s1ap_ptr->sctp_send_s1ap_pdu(tx_pdu, ctxt.rnti, "UplinkNASTransport");
}
bool s1ap::ue::send_uectxtreleaserequest(const cause_c& cause)
{
if (not ctxt.mme_ue_s1ap_id.has_value()) {
logger.error("Cannot send UE context release request without a MME-UE-S1AP-Id allocated.");
s1ap_ptr->rrc->release_ue(ctxt.rnti);
s1ap_ptr->users.erase(this);
return false;
}
if (ts1_reloc_overall.is_running() and cause.type().value == asn1::s1ap::cause_c::types_opts::radio_network and
(cause.radio_network().value == asn1::s1ap::cause_radio_network_opts::user_inactivity or
cause.radio_network().value == asn1::s1ap::cause_radio_network_opts::radio_conn_with_ue_lost)) {
logger.info("Ignoring UE context release request from lower layers for UE rnti=0x%x performing S1 Handover.",
ctxt.rnti);
// Leave the UE context alive during S1 Handover until ts1_reloc_overall expiry. Ignore releases due to
// UE inactivity or RLF
return false;
}
if (was_uectxtrelease_requested()) {
// let timeout auto-remove user.
return false;
}
s1ap_pdu_c tx_pdu;
tx_pdu.set_init_msg().load_info_obj(ASN1_S1AP_ID_UE_CONTEXT_RELEASE_REQUEST);
ue_context_release_request_s& container = tx_pdu.init_msg().value.ue_context_release_request();
container->mme_ue_s1ap_id.value = ctxt.mme_ue_s1ap_id.value();
container->enb_ue_s1ap_id.value = ctxt.enb_ue_s1ap_id;
// Cause
container->cause.value = cause;
release_requested = s1ap_ptr->sctp_send_s1ap_pdu(tx_pdu, ctxt.rnti, "UEContextReleaseRequest");
if (not release_requested) {
s1ap_ptr->rrc->release_ue(ctxt.rnti);
s1ap_ptr->users.erase(this);
} else {
overall_procedure_timeout.set(10000, [this](uint32_t tid) {
logger.warning("UE context for RNTI:0x%x is in zombie state. Releasing...", ctxt.rnti);
s1ap_ptr->rrc->release_ue(ctxt.rnti);
s1ap_ptr->users.erase(this);
});
overall_procedure_timeout.run();
}
return release_requested;
}
bool s1ap::ue::send_uectxtreleasecomplete()
{
overall_procedure_timeout.stop();
s1ap_pdu_c tx_pdu;
tx_pdu.set_successful_outcome().load_info_obj(ASN1_S1AP_ID_UE_CONTEXT_RELEASE);
auto& container = tx_pdu.successful_outcome().value.ue_context_release_complete();
container->enb_ue_s1ap_id.value = ctxt.enb_ue_s1ap_id;
container->mme_ue_s1ap_id.value = ctxt.mme_ue_s1ap_id.value();
// Stop TS1 Reloc Overall
ts1_reloc_overall.stop();
// Log event.
event_logger::get().log_s1_ctx_delete(ctxt.enb_cc_idx, ctxt.mme_ue_s1ap_id.value(), ctxt.enb_ue_s1ap_id, ctxt.rnti);
return s1ap_ptr->sctp_send_s1ap_pdu(tx_pdu, ctxt.rnti, "UEContextReleaseComplete");
}
void s1ap::ue::notify_rrc_reconf_complete()
{
if (current_state == s1ap_elem_procs_o::init_msg_c::types_opts::init_context_setup_request) {
logger.info("Procedure %s,rnti=0x%x - Received RRC reconf complete. Finishing UE context setup.",
s1ap_elem_procs_o::init_msg_c::types_opts{current_state}.to_string(),
ctxt.rnti);
ue_ctxt_setup_complete();
return;
}
}
void s1ap::ue::ue_ctxt_setup_complete()
{
if (current_state != s1ap_elem_procs_o::init_msg_c::types_opts::init_context_setup_request) {
logger.warning("Procedure %s,rnti=0x%x - Received unexpected complete notification",
s1ap_elem_procs_o::init_msg_c::types_opts{current_state}.to_string(),
ctxt.rnti);
return;
}
current_state = s1ap_elem_procs_o::init_msg_c::types_opts::nulltype;
s1ap_pdu_c tx_pdu;
if (updated_erabs.empty()) {
// It is ICS Failure
tx_pdu.set_unsuccessful_outcome().load_info_obj(ASN1_S1AP_ID_INIT_CONTEXT_SETUP);
auto& container = tx_pdu.unsuccessful_outcome().value.init_context_setup_fail();
container->enb_ue_s1ap_id.value = ctxt.enb_ue_s1ap_id;
container->mme_ue_s1ap_id.value = ctxt.mme_ue_s1ap_id.value();
if (not failed_cfg_erabs.empty()) {
container->cause.value = failed_cfg_erabs.front().cause;
} else {
logger.warning("Procedure %s,rnti=0x%x - no specified cause for failed configuration",
s1ap_elem_procs_o::init_msg_c::types_opts{current_state}.to_string(),
ctxt.rnti);
container->cause.value.set_misc().value = cause_misc_opts::unspecified;
}
s1ap_ptr->sctp_send_s1ap_pdu(tx_pdu, ctxt.rnti, "UEContextModificationFailure");
return;
}
// It is ICS Response
tx_pdu.set_successful_outcome().load_info_obj(ASN1_S1AP_ID_INIT_CONTEXT_SETUP);
auto& container = tx_pdu.successful_outcome().value.init_context_setup_resp();
// Fill in the MME and eNB IDs
container->mme_ue_s1ap_id.value = ctxt.mme_ue_s1ap_id.value();
container->enb_ue_s1ap_id.value = ctxt.enb_ue_s1ap_id;
// Add list of E-RABs that were not setup
if (not failed_cfg_erabs.empty()) {
container->erab_failed_to_setup_list_ctxt_su_res_present = true;
fill_erab_failed_setup_list(container->erab_failed_to_setup_list_ctxt_su_res.value, failed_cfg_erabs);
}
// Add setup E-RABs
container->erab_setup_list_ctxt_su_res.value.resize(updated_erabs.size());
for (size_t i = 0; i < updated_erabs.size(); ++i) {
container->erab_setup_list_ctxt_su_res.value[i].load_info_obj(ASN1_S1AP_ID_ERAB_SETUP_ITEM_CTXT_SU_RES);
auto& item = container->erab_setup_list_ctxt_su_res.value[i]->erab_setup_item_ctxt_su_res();
item.erab_id = updated_erabs[i];
get_erab_addr(item.erab_id, item.transport_layer_address, item.gtp_teid);
}
// Log event.
event_logger::get().log_s1_ctx_create(ctxt.enb_cc_idx, ctxt.mme_ue_s1ap_id.value(), ctxt.enb_ue_s1ap_id, ctxt.rnti);
s1ap_ptr->sctp_send_s1ap_pdu(tx_pdu, ctxt.rnti, "InitialContextSetupResponse");
}
bool s1ap::ue::send_erab_setup_response(const erab_id_list& erabs_setup, const erab_item_list& erabs_failed)
{
asn1::s1ap::s1ap_pdu_c tx_pdu;
tx_pdu.set_successful_outcome().load_info_obj(ASN1_S1AP_ID_ERAB_SETUP);
erab_setup_resp_s& res = tx_pdu.successful_outcome().value.erab_setup_resp();
// Fill in the MME and eNB IDs
res->mme_ue_s1ap_id.value = ctxt.mme_ue_s1ap_id.value();
res->enb_ue_s1ap_id.value = ctxt.enb_ue_s1ap_id;
// Add list of E-RABs that were not setup
if (not erabs_failed.empty()) {
res->erab_failed_to_setup_list_bearer_su_res_present = true;
fill_erab_failed_setup_list(res->erab_failed_to_setup_list_bearer_su_res.value, erabs_failed);
}
if (not erabs_setup.empty()) {
res->erab_setup_list_bearer_su_res_present = true;
res->erab_setup_list_bearer_su_res.value.resize(erabs_setup.size());
for (size_t i = 0; i < erabs_setup.size(); ++i) {
res->erab_setup_list_bearer_su_res.value[i].load_info_obj(ASN1_S1AP_ID_ERAB_SETUP_ITEM_BEARER_SU_RES);
auto& item = res->erab_setup_list_bearer_su_res.value[i]->erab_setup_item_bearer_su_res();
item.erab_id = erabs_setup[i];
get_erab_addr(item.erab_id, item.transport_layer_address, item.gtp_teid);
}
}
return s1ap_ptr->sctp_send_s1ap_pdu(tx_pdu, ctxt.rnti, "E_RABSetupResponse");
}
bool s1ap::ue::send_uectxtmodifyresp()
{
if (not s1ap_ptr->mme_connected) {
return false;
}
s1ap_pdu_c tx_pdu;
tx_pdu.set_successful_outcome().load_info_obj(ASN1_S1AP_ID_UE_CONTEXT_MOD);
auto& container = tx_pdu.successful_outcome().value.ue_context_mod_resp();
container->enb_ue_s1ap_id.value = ctxt.enb_ue_s1ap_id;
container->mme_ue_s1ap_id.value = ctxt.mme_ue_s1ap_id.value();
return s1ap_ptr->sctp_send_s1ap_pdu(tx_pdu, ctxt.rnti, "UEContextModificationResponse");
}
bool s1ap::ue::send_uectxtmodifyfailure(const cause_c& cause)
{
if (not s1ap_ptr->mme_connected) {
return false;
}
s1ap_pdu_c tx_pdu;
tx_pdu.set_unsuccessful_outcome().load_info_obj(ASN1_S1AP_ID_UE_CONTEXT_MOD);
auto& container = tx_pdu.unsuccessful_outcome().value.ue_context_mod_fail();
container->enb_ue_s1ap_id.value = ctxt.enb_ue_s1ap_id;
container->mme_ue_s1ap_id.value = ctxt.mme_ue_s1ap_id.value();
container->cause.value = cause;
return s1ap_ptr->sctp_send_s1ap_pdu(tx_pdu, ctxt.rnti, "UEContextModificationFailure");
}
/**
* @brief eNB sends MME to "E-RAB RELEASE RESPONSE"
* @remark TS 36.413, Section 8.2.3.2 - E-RAB Release - MME initiated (successful operation)
* @param erabs_successfully_released
* @param erabs_failed_to_release
* @return true if message was sent
*/
bool s1ap::ue::send_erab_release_response(const erab_id_list& erabs_released, const erab_item_list& erabs_failed)
{
asn1::s1ap::s1ap_pdu_c tx_pdu;
tx_pdu.set_successful_outcome().load_info_obj(ASN1_S1AP_ID_ERAB_RELEASE);
auto& container = tx_pdu.successful_outcome().value.erab_release_resp();
container->enb_ue_s1ap_id.value = ctxt.enb_ue_s1ap_id;
container->mme_ue_s1ap_id.value = ctxt.mme_ue_s1ap_id.value();
// Fill in which E-RABs were successfully released
if (not erabs_released.empty()) {
container->erab_release_list_bearer_rel_comp_present = true;
container->erab_release_list_bearer_rel_comp.value.resize(erabs_released.size());
for (size_t i = 0; i < erabs_released.size(); ++i) {
container->erab_release_list_bearer_rel_comp.value[i].load_info_obj(
ASN1_S1AP_ID_ERAB_RELEASE_ITEM_BEARER_REL_COMP);
container->erab_release_list_bearer_rel_comp.value[i]->erab_release_item_bearer_rel_comp().erab_id =
erabs_released[i];
}
}
// Fill in which E-RABs were *not* successfully released
if (not erabs_failed.empty()) {
container->erab_failed_to_release_list_present = true;
fill_erab_failed_setup_list(container->erab_failed_to_release_list.value, erabs_failed);
}
return s1ap_ptr->sctp_send_s1ap_pdu(tx_pdu, ctxt.rnti, "E-RABReleaseResponse");
}
bool s1ap::ue::send_erab_modify_response(const erab_id_list& erabs_modified, const erab_item_list& erabs_failed)
{
asn1::s1ap::s1ap_pdu_c tx_pdu;
tx_pdu.set_successful_outcome().load_info_obj(ASN1_S1AP_ID_ERAB_MODIFY);
auto& container = tx_pdu.successful_outcome().value.erab_modify_resp();
container->enb_ue_s1ap_id.value = ctxt.enb_ue_s1ap_id;
container->mme_ue_s1ap_id.value = ctxt.mme_ue_s1ap_id.value();
// Fill in which E-RABs were successfully released
if (not erabs_modified.empty()) {
container->erab_modify_list_bearer_mod_res_present = true;
container->erab_modify_list_bearer_mod_res.value.resize(erabs_modified.size());
for (uint32_t i = 0; i < container->erab_modify_list_bearer_mod_res.value.size(); i++) {
container->erab_modify_list_bearer_mod_res.value[i].load_info_obj(ASN1_S1AP_ID_ERAB_MODIFY_ITEM_BEARER_MOD_RES);
container->erab_modify_list_bearer_mod_res.value[i]->erab_modify_item_bearer_mod_res().erab_id =
erabs_modified[i];
}
}
// Fill in which E-RABs were *not* successfully released
if (not erabs_failed.empty()) {
container->erab_failed_to_modify_list_present = true;
fill_erab_failed_setup_list(container->erab_failed_to_modify_list.value, erabs_failed);
}
return s1ap_ptr->sctp_send_s1ap_pdu(tx_pdu, ctxt.rnti, "E-RABModifyResponse");
}
bool s1ap::ue::send_erab_release_indication(const std::vector<uint16_t>& erabs_successfully_released)
{
if (not erabs_successfully_released.empty()) {
logger.error("Failed to initiate E-RAB RELEASE INDICATION procedure for user rnti=0x%x", ctxt.rnti);
return false;
}
asn1::s1ap::s1ap_pdu_c tx_pdu;
tx_pdu.set_init_msg().load_info_obj(ASN1_S1AP_ID_ERAB_RELEASE_IND);
erab_release_ind_s& container = tx_pdu.init_msg().value.erab_release_ind();
container->enb_ue_s1ap_id.value = ctxt.enb_ue_s1ap_id;
container->mme_ue_s1ap_id.value = ctxt.mme_ue_s1ap_id.value();
// Fill in which E-RABs were successfully released
container->erab_released_list.value.resize(erabs_successfully_released.size());
for (size_t i = 0; i < container->erab_released_list.value.size(); ++i) {
container->erab_released_list.value[i].load_info_obj(ASN1_S1AP_ID_ERAB_ITEM);
container->erab_released_list.value[i]->erab_item().erab_id = erabs_successfully_released[i];
}
return s1ap_ptr->sctp_send_s1ap_pdu(tx_pdu, ctxt.rnti, "E-RABReleaseIndication");
}
bool s1ap::ue::send_ue_cap_info_indication(srsran::unique_byte_buffer_t ue_radio_cap)
{
asn1::s1ap::s1ap_pdu_c tx_pdu;
tx_pdu.set_init_msg().load_info_obj(ASN1_S1AP_ID_UE_CAP_INFO_IND);
ue_cap_info_ind_s& container = tx_pdu.init_msg().value.ue_cap_info_ind();
container->enb_ue_s1ap_id.value = ctxt.enb_ue_s1ap_id;
container->mme_ue_s1ap_id.value = ctxt.mme_ue_s1ap_id.value();
container->ue_radio_cap.value.resize(ue_radio_cap->N_bytes);
memcpy(container->ue_radio_cap.value.data(), ue_radio_cap->msg, ue_radio_cap->N_bytes);
return s1ap_ptr->sctp_send_s1ap_pdu(tx_pdu, ctxt.rnti, "UECapabilityInfoIndication");
}
void s1ap::ue::send_ho_cancel(const asn1::s1ap::cause_c& cause)
{
// Stop handover timers
ts1_reloc_prep.stop();
ts1_reloc_overall.stop();
// Send S1AP Handover Cancel
s1ap_pdu_c tx_pdu;
tx_pdu.set_init_msg().load_info_obj(ASN1_S1AP_ID_HO_CANCEL);
ho_cancel_s& container = tx_pdu.init_msg().value.ho_cancel();
container->mme_ue_s1ap_id.value = ctxt.mme_ue_s1ap_id.value();
container->enb_ue_s1ap_id.value = ctxt.enb_ue_s1ap_id;
container->cause.value = cause;
s1ap_ptr->sctp_send_s1ap_pdu(tx_pdu, ctxt.rnti, "HandoverCancel");
}
void s1ap::ue::set_state(s1ap_proc_id_t next_state,
const erab_id_list& erabs_updated,
const erab_item_list& erabs_failed_to_modify)
{
current_state = next_state;
updated_erabs.assign(erabs_updated.begin(), erabs_updated.end());
failed_cfg_erabs.assign(erabs_failed_to_modify.begin(), erabs_failed_to_modify.end());
}
void s1ap::ue::get_erab_addr(uint16_t erab_id, transp_addr_t& transp_addr, asn1::fixed_octstring<4, true>& gtpu_teid_id)
{
uint32_t teidin = 0;
int ret = s1ap_ptr->rrc->get_erab_addr_in(ctxt.rnti, erab_id, transp_addr, teidin);
srsran_expect(ret == SRSRAN_SUCCESS, "Invalid E-RAB setup");
// Note: RRC does not yet update correctly gtpu transp_addr
transp_addr.resize(32);
uint8_t addr[4];
if (!s1ap_ptr->args.gtp_advertise_addr.empty()) {
if (inet_pton(AF_INET, s1ap_ptr->args.gtp_advertise_addr.c_str(), addr) != 1) {
logger.error("Invalid gtp_advertise_addr: %s", s1ap_ptr->args.gtp_advertise_addr.c_str());
srsran::console("Invalid gtp_advertise_addr: %s\n", s1ap_ptr->args.gtp_advertise_addr.c_str());
perror("inet_pton");
}
} else {
if (inet_pton(AF_INET, s1ap_ptr->args.gtp_bind_addr.c_str(), addr) != 1) {
logger.error("Invalid gtp_bind_addr: %s", s1ap_ptr->args.gtp_bind_addr.c_str());
srsran::console("Invalid gtp_bind_addr: %s\n", s1ap_ptr->args.gtp_bind_addr.c_str());
perror("inet_pton");
}
}
for (uint32_t j = 0; j < 4; ++j) {
transp_addr.data()[j] = addr[3 - j];
}
gtpu_teid_id.from_number(teidin);
}
/*********************
* Handover Messages
********************/
bool s1ap::send_ho_required(uint16_t rnti,
uint32_t target_eci,
uint16_t target_tac,
srsran::plmn_id_t target_plmn,
srsran::span<uint32_t> fwd_erabs,
srsran::unique_byte_buffer_t rrc_container,
bool has_direct_fwd_path)
{
if (!mme_connected) {
return false;
}
ue* u = users.find_ue_rnti(rnti);
if (u == nullptr) {
return false;
}
// launch procedure
if (not u->ho_prep_proc.launch(
target_eci, target_tac, target_plmn, fwd_erabs, std::move(rrc_container), has_direct_fwd_path)) {
logger.error("Failed to initiate an HandoverPreparation procedure for user rnti=0x%x", u->ctxt.rnti);
return false;
}
return true;
}
bool s1ap::send_enb_status_transfer_proc(uint16_t rnti, std::vector<bearer_status_info>& bearer_status_list)
{
if (not mme_connected) {
return false;
}
ue* u = users.find_ue_rnti(rnti);
if (u == nullptr) {
return false;
}
return u->send_enb_status_transfer_proc(bearer_status_list);
}
/*********************************************************
* s1ap::user_list class
*********************************************************/
s1ap::ue* s1ap::user_list::find_ue_rnti(uint16_t rnti)
{
if (rnti == SRSRAN_INVALID_RNTI) {
return nullptr;
}
auto it = std::find_if(
users.begin(), users.end(), [rnti](const user_list::pair_type& v) { return v.second->ctxt.rnti == rnti; });
return it != users.end() ? it->second.get() : nullptr;
}
s1ap::ue* s1ap::user_list::find_ue_enbid(uint32_t enbid)
{
auto it = users.find(enbid);
return (it != users.end()) ? it->second.get() : nullptr;
}
s1ap::ue* s1ap::user_list::find_ue_mmeid(uint32_t mmeid)
{
auto it = std::find_if(users.begin(), users.end(), [mmeid](const user_list::pair_type& v) {
return v.second->ctxt.mme_ue_s1ap_id == mmeid;
});
return it != users.end() ? it->second.get() : nullptr;
}
/**
* @brief Adds a user to the user list, avoiding any rnti, enb_s1ap_id, mme_s1ap_id duplication
* @param %user to be inserted
* @return ptr of inserted %user. If failure, returns nullptr
*/
s1ap::ue* s1ap::user_list::add_user(std::unique_ptr<s1ap::ue> user)
{
static srslog::basic_logger& logger = srslog::fetch_basic_logger("S1AP");
// Check for ID repetitions
if (find_ue_rnti(user->ctxt.rnti) != nullptr) {
logger.error("The user to be added with rnti=0x%x already exists", user->ctxt.rnti);
return nullptr;
}
if (find_ue_enbid(user->ctxt.enb_ue_s1ap_id) != nullptr) {
logger.error("The user to be added with enb id=%d already exists", user->ctxt.enb_ue_s1ap_id);
return nullptr;
}
if (user->ctxt.mme_ue_s1ap_id.has_value() and find_ue_mmeid(user->ctxt.mme_ue_s1ap_id.value()) != nullptr) {
logger.error("The user to be added with mme id=%d already exists", user->ctxt.mme_ue_s1ap_id.value());
return nullptr;
}
auto p = users.insert(std::make_pair(user->ctxt.enb_ue_s1ap_id, std::move(user)));
return p.second ? p.first->second.get() : nullptr;
}
void s1ap::user_list::erase(ue* ue_ptr)
{
static srslog::basic_logger& logger = srslog::fetch_basic_logger("S1AP");
auto it = users.find(ue_ptr->ctxt.enb_ue_s1ap_id);
if (it == users.end()) {
logger.error("User to be erased does not exist");
return;
}
users.erase(it);
}
/*******************************************************************************
/* General helpers
********************************************************************************/
bool s1ap::sctp_send_s1ap_pdu(const asn1::s1ap::s1ap_pdu_c& tx_pdu, uint32_t rnti, const char* procedure_name)
{
if (not mme_connected and rnti != SRSRAN_INVALID_RNTI) {
logger.error("Aborting %s for rnti=0x%x. Cause: MME is not connected.", procedure_name, rnti);
return false;
}
// Reset the state if it is a successful or unsuccessfull message
if (tx_pdu.type() == s1ap_pdu_c::types_opts::successful_outcome ||
tx_pdu.type() == s1ap_pdu_c::types_opts::unsuccessful_outcome) {
if (rnti != SRSRAN_INVALID_RNTI) {
s1ap::ue* u = users.find_ue_rnti(rnti);
if (u == nullptr) {
logger.warning("Could not find user for %s. RNTI=%x", procedure_name, rnti);
} else {
u->set_state(s1ap_proc_id_t::nulltype, {}, {});
}
}
}
srsran::unique_byte_buffer_t buf = srsran::make_byte_buffer();
if (buf == nullptr) {
logger.error("Fatal Error: Couldn't allocate buffer for %s.", procedure_name);
return false;
}
asn1::bit_ref bref(buf->msg, buf->get_tailroom());
if (tx_pdu.pack(bref) != asn1::SRSASN_SUCCESS) {
logger.error("Failed to pack TX PDU %s", procedure_name);
return false;
}
buf->N_bytes = bref.distance_bytes();
// Save message to PCAP
if (pcap != nullptr) {
pcap->write_s1ap(buf->msg, buf->N_bytes);
}
if (rnti != SRSRAN_INVALID_RNTI) {
logger.info(buf->msg, buf->N_bytes, "Tx S1AP SDU, %s, rnti=0x%x", procedure_name, rnti);
} else {
logger.info(buf->msg, buf->N_bytes, "Tx S1AP SDU, %s", procedure_name);
}
uint16_t streamid = rnti == SRSRAN_INVALID_RNTI ? NONUE_STREAM_ID : users.find_ue_rnti(rnti)->stream_id;
ssize_t n_sent = sctp_sendmsg(mme_socket.fd(),
buf->msg,
buf->N_bytes,
(struct sockaddr*)&mme_addr,
sizeof(struct sockaddr_in),
htonl(PPID),
0,
streamid,
0,
0);
if (n_sent == -1) {
if (rnti != SRSRAN_INVALID_RNTI) {
logger.error("Error: Failure at Tx S1AP SDU, %s, rnti=0x%x", procedure_name, rnti);
} else {
logger.error("Error: Failure at Tx S1AP SDU, %s", procedure_name);
}
return false;
}
return true;
}
/**
* Helper method to find user based on the enb_ue_s1ap_id stored in an S1AP Msg, and update mme_ue_s1ap_id
* @param enb_id enb_ue_s1ap_id value stored in S1AP message
* @param mme_id mme_ue_s1ap_id value stored in S1AP message
* @return pointer to user if it has been found
*/
s1ap::ue* s1ap::handle_s1apmsg_ue_id(uint32_t enb_id, uint32_t mme_id)
{
ue* user_ptr = users.find_ue_enbid(enb_id);
ue* user_mme_ptr = nullptr;
cause_c cause;
logger.info("Checking UE S1 logical connection. eNB UE S1AP ID=%d, MME UE S1AP ID=%d", enb_id, mme_id);
if (user_ptr != nullptr) {
if (user_ptr->ctxt.mme_ue_s1ap_id == mme_id) {
// No ID inconsistency found
return user_ptr;
}
user_mme_ptr = users.find_ue_mmeid(mme_id);
if (not user_ptr->ctxt.mme_ue_s1ap_id.has_value() and user_mme_ptr == nullptr) {
// First "returned message", no inconsistency found (see 36.413, Section 10.6)
user_ptr->ctxt.mme_ue_s1ap_id = mme_id;
return user_ptr;
}
// TS 36.413, Sec. 10.6 - If a node receives a first returned message that includes a remote AP ID (...)
logger.warning("MME UE S1AP ID=%d not found - discarding message", mme_id);
cause.set_radio_network().value = user_mme_ptr != nullptr ? cause_radio_network_opts::unknown_mme_ue_s1ap_id
: cause_radio_network_opts::unknown_pair_ue_s1ap_id;
} else {
// TS 36.413, Sec. 10.6 - If a node receives a message (other than the first or first returned messages) that
// includes AP ID(s) identifying (...)
user_mme_ptr = users.find_ue_mmeid(mme_id);
logger.warning("ENB UE S1AP ID=%d not found - discarding message", enb_id);
cause.set_radio_network().value = user_mme_ptr != nullptr ? cause_radio_network_opts::unknown_enb_ue_s1ap_id
: cause_radio_network_opts::unknown_pair_ue_s1ap_id;
}
// the node shall initiate an Error Indication procedure with inclusion of the received AP ID(s) from the peer node
// and an appropriate cause value.
send_error_indication(cause, enb_id, mme_id);
// Both nodes shall initiate a local release of any established UE-associated logical connection (for the same S1
// interface) having the erroneous AP ID(s) as local or remote identifier.
if (user_ptr != nullptr) {
rrc->release_ue(user_ptr->ctxt.rnti);
}
if (user_mme_ptr != nullptr and user_mme_ptr != user_ptr) {
rrc->release_ue(user_mme_ptr->ctxt.rnti);
}
return nullptr;
}
std::string s1ap::get_cause(const cause_c& c)
{
std::string cause = c.type().to_string();
cause += " - ";
switch (c.type().value) {
case cause_c::types_opts::radio_network:
cause += c.radio_network().to_string();
break;
case cause_c::types_opts::transport:
cause += c.transport().to_string();
break;
case cause_c::types_opts::nas:
cause += c.nas().to_string();
break;
case cause_c::types_opts::protocol:
cause += c.protocol().to_string();
break;
case cause_c::types_opts::misc:
cause += c.misc().to_string();
break;
default:
cause += "unknown";
break;
}
return cause;
}
void s1ap::start_pcap(srsran::s1ap_pcap* pcap_)
{
pcap = pcap_;
}
/*******************************************************************************
/* s1ap::ue Class
********************************************************************************/
s1ap::ue::ue(s1ap* s1ap_ptr_) : s1ap_ptr(s1ap_ptr_), ho_prep_proc(this), logger(s1ap_ptr->logger)
{
ctxt.enb_ue_s1ap_id = s1ap_ptr->next_enb_ue_s1ap_id++;
gettimeofday(&ctxt.init_timestamp, nullptr);
stream_id = s1ap_ptr->next_ue_stream_id;
// initialize timers
ts1_reloc_prep = s1ap_ptr->task_sched.get_unique_timer();
ts1_reloc_prep.set(s1ap_ptr->args.ts1_reloc_prep_timeout,
[this](uint32_t tid) { ho_prep_proc.trigger(ho_prep_proc_t::ts1_reloc_prep_expired{}); });
ts1_reloc_overall = s1ap_ptr->task_sched.get_unique_timer();
ts1_reloc_overall.set(s1ap_ptr->args.ts1_reloc_overall_timeout, [this](uint32_t tid) {
//> If the UE Context Release procedure is not initiated towards the eNB before the expiry of the timer
// TS1RELOCOverall, the eNB shall request the MME to release the UE context.
s1ap_ptr->user_release(ctxt.rnti, asn1::s1ap::cause_radio_network_opts::ts1relocoverall_expiry);
});
overall_procedure_timeout = s1ap_ptr->task_sched.get_unique_timer();
overall_procedure_timeout.set(10000);
}
bool s1ap::ue::send_ho_required(uint32_t target_eci,
uint16_t target_tac,
srsran::plmn_id_t target_plmn,
srsran::span<uint32_t> fwd_erabs,
srsran::unique_byte_buffer_t rrc_container,
bool has_direct_fwd_path)
{
/*** Setup S1AP PDU as HandoverRequired ***/
s1ap_pdu_c tx_pdu;
tx_pdu.set_init_msg().load_info_obj(ASN1_S1AP_ID_HO_PREP);
ho_required_s& container = tx_pdu.init_msg().value.ho_required();
/*** fill HO Required message ***/
container->enb_ue_s1ap_id.value = ctxt.enb_ue_s1ap_id;
container->mme_ue_s1ap_id.value = ctxt.mme_ue_s1ap_id.value();
container->handov_type.value.value = handov_type_opts::intralte; // NOTE: only intra-LTE HO supported
container->cause.value.set_radio_network().value = cause_radio_network_opts::ho_desirable_for_radio_reason;
container->direct_forwarding_path_availability_present = has_direct_fwd_path;
if (container->direct_forwarding_path_availability_present) {
container->direct_forwarding_path_availability.value.value =
asn1::s1ap::direct_forwarding_path_availability_opts::direct_path_available;
}
/*** set the target eNB ***/
container->csg_id_present = false; // NOTE: CSG/hybrid target cell not supported
container->cell_access_mode_present = false; // only for hybrid cells
// no GERAN/UTRAN/PS
auto& targetenb = container->target_id.value.set_targetenb_id();
// set PLMN and TAI of target
// NOTE: Only HO without TAU supported.
uint16_t tmp16;
tmp16 = htons(target_tac);
memcpy(targetenb.sel_tai.tac.data(), &tmp16, sizeof(uint16_t));
target_plmn.to_s1ap_plmn_bytes(targetenb.sel_tai.plm_nid.data());
// NOTE: Only HO to different Macro eNB is supported.
auto& macroenb = targetenb.global_enb_id.enb_id.set_macro_enb_id();
target_plmn.to_s1ap_plmn_bytes(targetenb.global_enb_id.plm_nid.data());
macroenb.from_number(target_eci >> 8U);
/*** fill the transparent container ***/
container->source_to_target_transparent_container_secondary_present = false;
sourceenb_to_targetenb_transparent_container_s transparent_cntr;
transparent_cntr.subscriber_profile_idfor_rfp_present = false; // TODO: CHECK
transparent_cntr.erab_info_list_present = true;
transparent_cntr.erab_info_list.resize(fwd_erabs.size());
for (uint32_t i = 0; i < fwd_erabs.size(); ++i) {
transparent_cntr.erab_info_list[i].load_info_obj(ASN1_S1AP_ID_ERAB_INFO_LIST_ITEM);
transparent_cntr.erab_info_list[i]->erab_info_list_item().erab_id = fwd_erabs[i];
transparent_cntr.erab_info_list[i]->erab_info_list_item().dl_forwarding_present = true;
transparent_cntr.erab_info_list[i]->erab_info_list_item().dl_forwarding.value =
dl_forwarding_opts::dl_forwarding_proposed;
}
// - set target cell ID
target_plmn.to_s1ap_plmn_bytes(transparent_cntr.target_cell_id.plm_nid.data());
transparent_cntr.target_cell_id.cell_id.from_number(target_eci); // [ENBID|CELLID|0]
// info specific to source cell and history of UE
// - set as last visited cell the source eNB PLMN & Cell ID
transparent_cntr.ue_history_info.resize(1);
auto& eutra = transparent_cntr.ue_history_info[0].set_e_utran_cell();
eutra.cell_type.cell_size.value = cell_size_opts::medium;
target_plmn.to_s1ap_plmn_bytes(eutra.global_cell_id.plm_nid.data());
eutra.global_cell_id.cell_id = s1ap_ptr->eutran_cgi.cell_id;
// - set time spent in current source cell
struct timeval ts[3];
memcpy(&ts[1], &ctxt.init_timestamp, sizeof(struct timeval));
gettimeofday(&ts[2], nullptr);
get_time_interval(ts);
eutra.time_ue_stayed_in_cell = (uint16_t)(ts[0].tv_usec / 1.0e6 + ts[0].tv_sec);
eutra.time_ue_stayed_in_cell = std::min(eutra.time_ue_stayed_in_cell, (uint16_t)4095);
// - fill RRC container
transparent_cntr.rrc_container.resize(rrc_container->N_bytes);
memcpy(transparent_cntr.rrc_container.data(), rrc_container->msg, rrc_container->N_bytes);
// pack Transparent Container into HORequired message
srsran::unique_byte_buffer_t buffer = srsran::make_byte_buffer();
if (buffer == nullptr) {
logger.error("Failed to allocate buffer for HORequired message packing");
return false;
}
asn1::bit_ref bref(buffer->msg, buffer->get_tailroom());
if (transparent_cntr.pack(bref) != asn1::SRSASN_SUCCESS) {
logger.error("Failed to pack transparent container of HO Required message");
return false;
}
container->source_to_target_transparent_container.value.resize(bref.distance_bytes());
memcpy(container->source_to_target_transparent_container.value.data(), buffer->msg, bref.distance_bytes());
// Send to HandoverRequired message to MME
return s1ap_ptr->sctp_send_s1ap_pdu(tx_pdu, ctxt.rnti, "Handover Required");
}
bool s1ap::ue::send_enb_status_transfer_proc(std::vector<bearer_status_info>& bearer_status_list)
{
if (bearer_status_list.empty()) {
return false;
}
s1ap_pdu_c tx_pdu;
tx_pdu.set_init_msg().load_info_obj(ASN1_S1AP_ID_ENB_STATUS_TRANSFER);
enb_status_transfer_s& container = tx_pdu.init_msg().value.enb_status_transfer();
container->enb_ue_s1ap_id.value = ctxt.enb_ue_s1ap_id;
container->mme_ue_s1ap_id.value = ctxt.mme_ue_s1ap_id.value();
/* Create StatusTransfer transparent container with all the bearer ctxt to transfer */
auto& list = container->enb_status_transfer_transparent_container.value.bearers_subject_to_status_transfer_list;
list.resize(bearer_status_list.size());
for (uint32_t i = 0; i < list.size(); ++i) {
list[i].load_info_obj(ASN1_S1AP_ID_BEARERS_SUBJECT_TO_STATUS_TRANSFER_ITEM);
auto& asn1bearer = list[i]->bearers_subject_to_status_transfer_item();
bearer_status_info& item = bearer_status_list[i];
asn1bearer.erab_id = item.erab_id;
asn1bearer.dl_coun_tvalue.pdcp_sn = item.pdcp_dl_sn;
asn1bearer.dl_coun_tvalue.hfn = item.dl_hfn;
asn1bearer.ul_coun_tvalue.pdcp_sn = item.pdcp_ul_sn;
asn1bearer.ul_coun_tvalue.hfn = item.ul_hfn;
// TODO: asn1bearer.receiveStatusofULPDCPSDUs_present
// asn1::json_writer jw;
// asn1bearer.to_json(jw);
// printf("Bearer to add %s", jw.to_string().c_str());
}
return s1ap_ptr->sctp_send_s1ap_pdu(tx_pdu, ctxt.rnti, "ENBStatusTransfer");
}
void s1ap::log_s1ap_msg(const asn1::s1ap::s1ap_pdu_c& msg, srsran::const_span<uint8_t> sdu, bool is_rx)
{
const char* msg_type;
switch (msg.type().value) {
case s1ap_pdu_c::types_opts::init_msg:
msg_type = msg.init_msg().value.type().to_string();
break;
case s1ap_pdu_c::types_opts::successful_outcome:
msg_type = msg.successful_outcome().value.type().to_string();
break;
case s1ap_pdu_c::types_opts::unsuccessful_outcome:
msg_type = msg.unsuccessful_outcome().value.type().to_string();
break;
default:
logger.warning("Unrecognized S1AP message type\n");
return;
}
logger.info(sdu.data(), sdu.size(), "%s S1AP SDU - %s", is_rx ? "Rx" : "Tx", msg_type);
}
} // namespace srsenb
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