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/*
* Copyright 2013-2019 Software Radio Systems Limited
*
* This file is part of srsLTE.
*
* srsLTE 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.
*
* srsLTE 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/.
*
*/
#ifndef SRSLTE_RLC_AM_H
#define SRSLTE_RLC_AM_H
#include "srslte/common/buffer_pool.h"
#include "srslte/common/log.h"
#include "srslte/common/common.h"
#include "srslte/interfaces/ue_interfaces.h"
#include "srslte/upper/rlc_tx_queue.h"
#include "srslte/common/timeout.h"
#include "srslte/upper/rlc_common.h"
#include <map>
#include <deque>
#include <list>
namespace srslte {
#undef RLC_AM_BUFFER_DEBUG
struct rlc_amd_rx_pdu_t{
rlc_amd_pdu_header_t header;
unique_byte_buffer_t buf;
};
struct rlc_amd_rx_pdu_segments_t{
std::list<rlc_amd_rx_pdu_t> segments;
};
struct rlc_amd_tx_pdu_t{
rlc_amd_pdu_header_t header;
unique_byte_buffer_t buf;
uint32_t retx_count;
bool is_acked;
};
struct rlc_amd_retx_t{
uint32_t sn;
bool is_segment;
uint32_t so_start;
uint32_t so_end;
};
class rlc_am : public rlc_common
{
public:
rlc_am(srslte::log* log_,
uint32_t lcid_,
srsue::pdcp_interface_rlc* pdcp_,
srsue::rrc_interface_rlc* rrc_,
srslte::timer_handler* timers_);
bool configure(rlc_config_t cfg_);
void reestablish();
void stop();
void empty_queue();
rlc_mode_t get_mode();
uint32_t get_bearer();
// PDCP interface
void write_sdu(unique_byte_buffer_t sdu, bool blocking = true);
// MAC interface
bool has_data();
uint32_t get_buffer_state();
int read_pdu(uint8_t *payload, uint32_t nof_bytes);
void write_pdu(uint8_t *payload, uint32_t nof_bytes);
uint32_t get_num_tx_bytes();
uint32_t get_num_rx_bytes();
void reset_metrics();
private:
// Transmitter sub-class
class rlc_am_tx : public timer_callback
{
public:
rlc_am_tx(rlc_am* parent_);
~rlc_am_tx();
bool configure(rlc_config_t cfg_);
void empty_queue();
void reestablish();
void stop();
void write_sdu(unique_byte_buffer_t sdu, bool blocking);
int read_pdu(uint8_t *payload, uint32_t nof_bytes);
bool has_data();
uint32_t get_buffer_state();
uint32_t get_num_tx_bytes();
void reset_metrics();
// Timeout callback interface
void timer_expired(uint32_t timeout_id);
// Interface for Rx subclass
void handle_control_pdu(uint8_t *payload, uint32_t nof_bytes);
private:
int build_status_pdu(uint8_t *payload, uint32_t nof_bytes);
int build_retx_pdu(uint8_t *payload, uint32_t nof_bytes);
int build_segment(uint8_t *payload, uint32_t nof_bytes, rlc_amd_retx_t retx);
int build_data_pdu(uint8_t *payload, uint32_t nof_bytes);
void debug_state();
bool retx_queue_has_sn(uint32_t sn);
int required_buffer_size(rlc_amd_retx_t retx);
void retransmit_random_pdu();
// Helpers
bool poll_required();
bool do_status();
rlc_am* parent = nullptr;
byte_buffer_pool* pool = nullptr;
srslte::log* log = nullptr;
/****************************************************************************
* Configurable parameters
* Ref: 3GPP TS 36.322 v10.0.0 Section 7
***************************************************************************/
rlc_am_config_t cfg = {};
// TX SDU buffers
rlc_tx_queue tx_sdu_queue;
unique_byte_buffer_t tx_sdu;
bool tx_enabled = false;
/****************************************************************************
* State variables and counters
* Ref: 3GPP TS 36.322 v10.0.0 Section 7
***************************************************************************/
// Tx state variables
uint32_t vt_a = 0; // ACK state. SN of next PDU in sequence to be ACKed. Low edge of tx window.
uint32_t vt_ms = RLC_AM_WINDOW_SIZE; // Max send state. High edge of tx window. vt_a + window_size.
uint32_t vt_s = 0; // Send state. SN to be assigned for next PDU.
uint32_t poll_sn = 0; // Poll send state. SN of most recent PDU txed with poll bit set.
// Tx counters
uint32_t pdu_without_poll = 0;
uint32_t byte_without_poll = 0;
rlc_status_pdu_t tx_status;
/****************************************************************************
* Timers
* Ref: 3GPP TS 36.322 v10.0.0 Section 7
***************************************************************************/
srslte::timer_handler::unique_timer poll_retx_timer;
srslte::timer_handler::unique_timer status_prohibit_timer;
// Tx windows
std::map<uint32_t, rlc_amd_tx_pdu_t> tx_window;
std::deque<rlc_amd_retx_t> retx_queue;
// Mutexes
pthread_mutex_t mutex;
// Metrics
uint32_t num_tx_bytes = 0;
};
// Receiver sub-class
class rlc_am_rx : public timer_callback
{
public:
rlc_am_rx(rlc_am* parent_);
~rlc_am_rx();
bool configure(rlc_am_config_t cfg_);
void reestablish();
void stop();
void write_pdu(uint8_t *payload, uint32_t nof_bytes);
uint32_t get_num_rx_bytes();
void reset_metrics();
// Timeout callback interface
void timer_expired(uint32_t timeout_id);
// Functions needed by Tx subclass to query rx state
int get_status_pdu_length();
int get_status_pdu(rlc_status_pdu_t* status, const uint32_t nof_bytes);
bool get_do_status();
void reset_status(); // called when status PDU has been sent
private:
void handle_data_pdu(uint8_t *payload, uint32_t nof_bytes, rlc_amd_pdu_header_t &header);
void handle_data_pdu_segment(uint8_t *payload, uint32_t nof_bytes, rlc_amd_pdu_header_t &header);
void reassemble_rx_sdus();
bool inside_rx_window(const int16_t sn);
void debug_state();
void print_rx_segments();
bool add_segment_and_check(rlc_amd_rx_pdu_segments_t *pdu, rlc_amd_rx_pdu_t *segment);
rlc_am* parent = nullptr;
byte_buffer_pool* pool = nullptr;
srslte::log* log = nullptr;
/****************************************************************************
* Configurable parameters
* Ref: 3GPP TS 36.322 v10.0.0 Section 7
***************************************************************************/
rlc_am_config_t cfg = {};
// RX SDU buffers
unique_byte_buffer_t rx_sdu;
/****************************************************************************
* State variables and counters
* Ref: 3GPP TS 36.322 v10.0.0 Section 7
***************************************************************************/
// Rx state variables
uint32_t vr_r = 0; // Receive state. SN following last in-sequence received PDU. Low edge of rx window
uint32_t vr_mr = RLC_AM_WINDOW_SIZE; // Max acceptable receive state. High edge of rx window. vr_r + window size.
uint32_t vr_x = 0; // t_reordering state. SN following PDU which triggered t_reordering.
uint32_t vr_ms = 0; // Max status tx state. Highest possible value of SN for ACK_SN in status PDU.
uint32_t vr_h = 0; // Highest rx state. SN following PDU with highest SN among rxed PDUs.
// Mutexes
pthread_mutex_t mutex;
// Rx windows
std::map<uint32_t, rlc_amd_rx_pdu_t> rx_window;
std::map<uint32_t, rlc_amd_rx_pdu_segments_t> rx_segments;
// Metrics
uint32_t num_rx_bytes = 0;
bool poll_received = false;
bool do_status = false;
/****************************************************************************
* Timers
* Ref: 3GPP TS 36.322 v10.0.0 Section 7
***************************************************************************/
srslte::timer_handler::unique_timer reordering_timer;
};
// Common variables needed/provided by parent class
srsue::rrc_interface_rlc* rrc = nullptr;
srslte::log* log = nullptr;
srsue::pdcp_interface_rlc* pdcp = nullptr;
srslte::timer_handler* timers = nullptr;
uint32_t lcid = 0;
rlc_config_t cfg = {};
std::string rb_name;
static const int poll_periodicity = 8; // After how many data PDUs a status PDU shall be requested
// Rx and Tx objects
rlc_am_tx tx;
rlc_am_rx rx;
};
/****************************************************************************
* Header pack/unpack helper functions
* Ref: 3GPP TS 36.322 v10.0.0 Section 6.2.1
***************************************************************************/
void rlc_am_read_data_pdu_header(byte_buffer_t *pdu, rlc_amd_pdu_header_t *header);
void rlc_am_read_data_pdu_header(uint8_t **payload, uint32_t *nof_bytes, rlc_amd_pdu_header_t *header);
void rlc_am_write_data_pdu_header(rlc_amd_pdu_header_t *header, byte_buffer_t *pdu);
void rlc_am_write_data_pdu_header(rlc_amd_pdu_header_t *header, uint8_t **payload);
void rlc_am_read_status_pdu(byte_buffer_t *pdu, rlc_status_pdu_t *status);
void rlc_am_read_status_pdu(uint8_t *payload, uint32_t nof_bytes, rlc_status_pdu_t *status);
void rlc_am_write_status_pdu(rlc_status_pdu_t *status, byte_buffer_t *pdu );
int rlc_am_write_status_pdu(rlc_status_pdu_t *status, uint8_t *payload);
uint32_t rlc_am_packed_length(rlc_amd_pdu_header_t *header);
uint32_t rlc_am_packed_length(rlc_status_pdu_t *status);
uint32_t rlc_am_packed_length(rlc_amd_retx_t retx);
bool rlc_am_is_valid_status_pdu(const rlc_status_pdu_t& status);
bool rlc_am_is_control_pdu(byte_buffer_t *pdu);
bool rlc_am_is_control_pdu(uint8_t *payload);
bool rlc_am_is_pdu_segment(uint8_t *payload);
std::string rlc_am_status_pdu_to_string(rlc_status_pdu_t *status);
std::string rlc_amd_pdu_header_to_string(const rlc_amd_pdu_header_t &header);
bool rlc_am_start_aligned(const uint8_t fi);
bool rlc_am_end_aligned(const uint8_t fi);
bool rlc_am_is_unaligned(const uint8_t fi);
bool rlc_am_not_start_aligned(const uint8_t fi);
} // namespace srslte
#endif // SRSLTE_RLC_AM_H