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srsRAN_4G/lib/include/srsran/rlc/rlc_am_data_structs.h

548 lines
16 KiB
C++

/**
* 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/.
*
*/
#ifndef SRSRAN_RLC_AM_DATA_STRUCTS_H
#define SRSRAN_RLC_AM_DATA_STRUCTS_H
#include "srsran/adt/circular_buffer.h"
#include "srsran/adt/circular_map.h"
#include "srsran/adt/intrusive_list.h"
#include "srsran/common/buffer_pool.h"
#include <array>
#include <list>
#include <vector>
namespace srsran {
template <typename HeaderType>
class rlc_amd_tx_pdu;
template <typename HeaderType>
class pdcp_pdu_info;
/// Pool that manages the allocation of RLC AM PDU Segments to RLC PDUs and tracking of segments ACK state
template <typename HeaderType>
struct rlc_am_pdu_segment_pool {
const static size_t MAX_POOL_SIZE = 16384;
/// RLC AM PDU Segment, containing the PDCP SN and RLC SN it has been assigned to, and its current ACK state
using rlc_list_tag = default_intrusive_tag;
struct free_list_tag {};
struct segment_resource : public intrusive_forward_list_element<rlc_list_tag>,
public intrusive_forward_list_element<free_list_tag>,
public intrusive_double_linked_list_element<> {
const static uint32_t invalid_rlc_sn = std::numeric_limits<uint32_t>::max();
const static uint32_t invalid_pdcp_sn = std::numeric_limits<uint32_t>::max() - 1; // -1 for Status Report
int id() const { return std::distance(parent_pool->segments.cbegin(), this); }
void release_pdcp_sn()
{
pdcp_sn_ = invalid_pdcp_sn;
if (empty()) {
parent_pool->free_list.push_front(this);
}
}
void release_rlc_sn()
{
rlc_sn_ = invalid_rlc_sn;
if (empty()) {
parent_pool->free_list.push_front(this);
}
}
uint32_t rlc_sn() const { return rlc_sn_; }
uint32_t pdcp_sn() const { return pdcp_sn_; }
bool empty() const { return rlc_sn_ == invalid_rlc_sn and pdcp_sn_ == invalid_pdcp_sn; }
private:
friend struct rlc_am_pdu_segment_pool<HeaderType>;
uint32_t rlc_sn_ = invalid_rlc_sn;
uint32_t pdcp_sn_ = invalid_pdcp_sn;
rlc_am_pdu_segment_pool<HeaderType>* parent_pool = nullptr;
};
rlc_am_pdu_segment_pool()
{
for (segment_resource& s : segments) {
s.parent_pool = this;
free_list.push_front(&s);
}
}
rlc_am_pdu_segment_pool(const rlc_am_pdu_segment_pool&) = delete;
rlc_am_pdu_segment_pool(rlc_am_pdu_segment_pool&&) = delete;
rlc_am_pdu_segment_pool& operator=(const rlc_am_pdu_segment_pool&) = delete;
rlc_am_pdu_segment_pool& operator=(rlc_am_pdu_segment_pool&&) = delete;
bool has_segments() const { return not free_list.empty(); }
bool make_segment(rlc_amd_tx_pdu<HeaderType>& rlc_list, pdcp_pdu_info<HeaderType>& pdcp_list)
{
if (not has_segments()) {
return false;
}
segment_resource* segment = free_list.pop_front();
segment->rlc_sn_ = rlc_list.rlc_sn;
segment->pdcp_sn_ = pdcp_list.sn;
rlc_list.add_segment(*segment);
pdcp_list.add_segment(*segment);
return true;
}
private:
intrusive_forward_list<rlc_am_pdu_segment_pool<HeaderType>::segment_resource, free_list_tag> free_list;
std::array<rlc_am_pdu_segment_pool<HeaderType>::segment_resource, MAX_POOL_SIZE> segments;
};
/// Class that contains the parameters and state (e.g. segments) of a RLC PDU
template <typename HeaderType>
class rlc_amd_tx_pdu
{
using rlc_am_pdu_segment = typename rlc_am_pdu_segment_pool<HeaderType>::segment_resource;
using list_type = intrusive_forward_list<rlc_am_pdu_segment>;
const static uint32_t invalid_rlc_sn = std::numeric_limits<uint32_t>::max();
list_type list;
public:
using iterator = typename list_type::iterator;
using const_iterator = typename list_type::const_iterator;
const uint32_t rlc_sn = invalid_rlc_sn;
uint32_t retx_count = 0;
HeaderType header = {};
unique_byte_buffer_t buf = nullptr;
explicit rlc_amd_tx_pdu(uint32_t rlc_sn_) : rlc_sn(rlc_sn_) {}
rlc_amd_tx_pdu(const rlc_amd_tx_pdu&) = delete;
rlc_amd_tx_pdu(rlc_amd_tx_pdu&& other) noexcept = default;
rlc_amd_tx_pdu& operator=(const rlc_amd_tx_pdu& other) = delete;
rlc_amd_tx_pdu& operator=(rlc_amd_tx_pdu&& other) = delete;
~rlc_amd_tx_pdu()
{
while (not list.empty()) {
// remove from list
rlc_am_pdu_segment* segment = list.pop_front();
// deallocate if also removed from PDCP
segment->release_rlc_sn();
}
}
// Segment List Interface
void add_segment(rlc_am_pdu_segment& segment) { list.push_front(&segment); }
const_iterator begin() const { return list.begin(); }
const_iterator end() const { return list.end(); }
iterator begin() { return list.begin(); }
iterator end() { return list.end(); }
};
/// Class that contains the parameters and state (e.g. unACKed segments) of a PDCP PDU
template <typename HeaderType>
class pdcp_pdu_info
{
using rlc_am_pdu_segment = typename rlc_am_pdu_segment_pool<HeaderType>::segment_resource;
using list_type = intrusive_double_linked_list<rlc_am_pdu_segment>;
list_type list; // List of unACKed RLC PDUs that contain segments that belong to the PDCP PDU.
public:
const static uint32_t status_report_sn = std::numeric_limits<uint32_t>::max();
const static uint32_t invalid_pdcp_sn = std::numeric_limits<uint32_t>::max() - 1;
using iterator = typename list_type::iterator;
using const_iterator = typename list_type::const_iterator;
// Copy is forbidden to avoid multiple PDCP SN references to the same segment
pdcp_pdu_info() = default;
pdcp_pdu_info(pdcp_pdu_info&&) noexcept = default;
pdcp_pdu_info(const pdcp_pdu_info&) noexcept = delete;
pdcp_pdu_info& operator=(const pdcp_pdu_info&) noexcept = delete;
pdcp_pdu_info& operator=(pdcp_pdu_info&&) noexcept = default;
~pdcp_pdu_info() { clear(); }
uint32_t sn = invalid_pdcp_sn;
bool fully_txed = false; // Boolean indicating if the SDU is fully transmitted.
bool fully_acked() const { return fully_txed and list.empty(); }
bool valid() const { return sn != invalid_pdcp_sn; }
// Interface for list of unACKed RLC segments of the PDCP PDU
void add_segment(rlc_am_pdu_segment& segment) { list.push_front(&segment); }
void ack_segment(rlc_am_pdu_segment& segment)
{
// remove from list
list.pop(&segment);
// signal pool that the pdcp handle is released
segment.release_pdcp_sn();
}
void clear()
{
sn = invalid_pdcp_sn;
fully_txed = false;
while (not list.empty()) {
ack_segment(list.front());
}
}
const_iterator begin() const { return list.begin(); }
const_iterator end() const { return list.end(); }
};
template <class T>
struct rlc_ringbuffer_base {
virtual ~rlc_ringbuffer_base() = default;
virtual T& add_pdu(size_t sn) = 0;
virtual void remove_pdu(size_t sn) = 0;
virtual T& operator[](size_t sn) = 0;
virtual size_t size() const = 0;
virtual bool empty() const = 0;
virtual bool full() const = 0;
virtual void clear() = 0;
virtual bool has_sn(uint32_t sn) const = 0;
};
template <class T, std::size_t WINDOW_SIZE>
struct rlc_ringbuffer_t : public rlc_ringbuffer_base<T> {
~rlc_ringbuffer_t() = default;
T& add_pdu(size_t sn) override
{
srsran_expect(not has_sn(sn), "The same SN=%zd should not be added twice", sn);
window.overwrite(sn, T(sn));
return window[sn];
}
void remove_pdu(size_t sn) override
{
srsran_expect(has_sn(sn), "The removed SN=%zd is not in the window", sn);
window.erase(sn);
}
T& operator[](size_t sn) override { return window[sn]; }
size_t size() const override { return window.size(); }
bool full() const override { return window.full(); }
bool empty() const override { return window.empty(); }
void clear() override { window.clear(); }
bool has_sn(uint32_t sn) const override { return window.contains(sn); }
// Return the sum data bytes of all active PDUs (check PDU is non-null)
uint32_t get_buffered_bytes()
{
uint32_t buff_size = 0;
for (const auto& pdu : window) {
if (pdu.second.buf != nullptr) {
buff_size += pdu.second.buf->N_bytes;
}
}
return buff_size;
}
private:
srsran::static_circular_map<uint32_t, T, WINDOW_SIZE> window;
};
template <typename HeaderType>
struct buffered_pdcp_pdu_list {
public:
explicit buffered_pdcp_pdu_list() : buffered_pdus(buffered_pdcp_pdu_list::buffer_size) { clear(); }
void clear()
{
count = 0;
for (pdcp_pdu_info<HeaderType>& b : buffered_pdus) {
b.clear();
}
}
void add_pdcp_sdu(uint32_t sn)
{
srsran_expect(sn <= max_pdcp_sn or sn == status_report_sn, "Invalid PDCP SN=%d", sn);
srsran_assert(not has_pdcp_sn(sn), "Cannot re-add same PDCP SN twice");
pdcp_pdu_info<HeaderType>& pdu = get_pdu_(sn);
if (pdu.valid()) {
pdu.clear();
count--;
}
pdu.sn = sn;
count++;
}
void clear_pdcp_sdu(uint32_t sn)
{
pdcp_pdu_info<HeaderType>& pdu = get_pdu_(sn);
if (not pdu.valid()) {
return;
}
pdu.clear();
count--;
}
pdcp_pdu_info<HeaderType>& operator[](uint32_t sn)
{
srsran_expect(has_pdcp_sn(sn), "Invalid access to non-existent PDCP SN=%d", sn);
return get_pdu_(sn);
}
bool has_pdcp_sn(uint32_t pdcp_sn) const
{
srsran_expect(pdcp_sn <= max_pdcp_sn or pdcp_sn == status_report_sn, "Invalid PDCP SN=%d", pdcp_sn);
return get_pdu_(pdcp_sn).sn == pdcp_sn;
}
uint32_t nof_sdus() const { return count; }
private:
const static size_t max_pdcp_sn = 262143u;
const static size_t buffer_size = 4096u;
const static uint32_t status_report_sn = pdcp_pdu_info<HeaderType>::status_report_sn;
pdcp_pdu_info<HeaderType>& get_pdu_(uint32_t sn)
{
return (sn == status_report_sn) ? status_report_pdu : buffered_pdus[static_cast<size_t>(sn % buffer_size)];
}
const pdcp_pdu_info<HeaderType>& get_pdu_(uint32_t sn) const
{
return (sn == status_report_sn) ? status_report_pdu : buffered_pdus[static_cast<size_t>(sn % buffer_size)];
}
// size equal to buffer_size
std::vector<pdcp_pdu_info<HeaderType> > buffered_pdus;
pdcp_pdu_info<HeaderType> status_report_pdu;
uint32_t count = 0;
};
struct rlc_amd_retx_base_t {
const static uint32_t invalid_rlc_sn = std::numeric_limits<uint32_t>::max();
uint32_t sn; ///< sequence number
bool is_segment; ///< flag whether this is a segment or not
uint32_t so_start; ///< offset to first byte of this segment
// so_end or segment_length are different for LTE and NR, hence are defined in subclasses
uint32_t current_so; ///< stores progressing SO during segmentation of this object
rlc_amd_retx_base_t() : sn(invalid_rlc_sn), is_segment(false), so_start(0), current_so(0) {}
virtual ~rlc_amd_retx_base_t() = default;
/**
* @brief overlaps implements a check whether the range of this retransmission object includes
* the given segment offset
* @param so the segment offset to check
* @return true if the segment offset is covered by the retransmission object. Otherwise false
*/
virtual bool overlaps(uint32_t so) const = 0;
};
struct rlc_amd_retx_lte_t : public rlc_amd_retx_base_t {
uint32_t so_end; ///< offset to first byte beyond the end of this segment
rlc_amd_retx_lte_t() : rlc_amd_retx_base_t(), so_end(0) {}
bool overlaps(uint32_t segment_offset) const override
{
return (segment_offset >= so_start) && (segment_offset < so_end);
}
};
struct rlc_amd_retx_nr_t : public rlc_amd_retx_base_t {
uint32_t segment_length; ///< number of bytes contained in this segment
rlc_amd_retx_nr_t() : rlc_amd_retx_base_t(), segment_length(0) {}
bool overlaps(uint32_t segment_offset) const override
{
return (segment_offset >= so_start) && (segment_offset < current_so + segment_length);
}
};
template <class T>
class pdu_retx_queue_base
{
public:
virtual ~pdu_retx_queue_base() = default;
virtual T& push() = 0;
virtual void pop() = 0;
virtual T& front() = 0;
virtual void clear() = 0;
virtual size_t size() const = 0;
virtual bool empty() const = 0;
virtual bool full() const = 0;
virtual T& operator[](size_t idx) = 0;
virtual const T& operator[](size_t idx) const = 0;
virtual bool has_sn(uint32_t sn) const = 0;
virtual bool has_sn(uint32_t sn, uint32_t so) const = 0;
};
template <class T, std::size_t WINDOW_SIZE>
class pdu_retx_queue : public pdu_retx_queue_base<T>
{
public:
~pdu_retx_queue() = default;
T& push() override
{
assert(not full());
T& p = buffer[wpos];
wpos = (wpos + 1) % WINDOW_SIZE;
return p;
}
void pop() override { rpos = (rpos + 1) % WINDOW_SIZE; }
T& front() override
{
assert(not empty());
return buffer[rpos];
}
T& operator[](size_t idx) override
{
srsran_assert(idx < size(), "Out-of-bounds access to element idx=%zd", idx);
return buffer[(rpos + idx) % WINDOW_SIZE];
}
const T& operator[](size_t idx) const override
{
srsran_assert(idx < size(), "Out-of-bounds access to element idx=%zd", idx);
return buffer[(rpos + idx) % WINDOW_SIZE];
}
void clear() override
{
wpos = 0;
rpos = 0;
}
bool has_sn(uint32_t sn) const override
{
for (size_t i = rpos; i != wpos; i = (i + 1) % WINDOW_SIZE) {
if (buffer[i].sn == sn) {
return true;
}
}
return false;
}
bool has_sn(uint32_t sn, uint32_t so) const override
{
for (size_t i = rpos; i != wpos; i = (i + 1) % WINDOW_SIZE) {
if (buffer[i].sn == sn) {
if (buffer[i].overlaps(so)) {
return true;
}
}
}
return false;
}
size_t size() const override { return (wpos >= rpos) ? wpos - rpos : WINDOW_SIZE + wpos - rpos; }
bool empty() const override { return wpos == rpos; }
bool full() const override { return size() == WINDOW_SIZE - 1; }
private:
std::array<T, WINDOW_SIZE> buffer;
size_t wpos = 0;
size_t rpos = 0;
};
template <class T>
class pdu_retx_queue_list
{
std::list<T> queue;
public:
~pdu_retx_queue_list() = default;
T& push()
{
queue.emplace_back();
return queue.back();
}
void pop()
{
if (not queue.empty()) {
queue.pop_front();
}
}
T& front()
{
assert(not queue.empty());
return queue.front();
}
const std::list<T>& get_inner_queue() const { return queue; }
void clear() { queue.clear(); }
size_t size() const { return queue.size(); }
bool empty() const { return queue.empty(); }
bool has_sn(uint32_t sn) const
{
if (queue.empty()) {
return false;
}
for (auto elem : queue) {
if (elem.sn == sn) {
return true;
}
}
return false;
};
bool has_sn(uint32_t sn, uint32_t so) const
{
if (queue.empty()) {
return false;
}
for (auto elem : queue) {
if (elem.sn == sn) {
if (elem.overlaps(so)) {
return true;
}
}
}
return false;
};
/**
* @brief remove_sn removes SN from queue and returns after first match
* @param sn sequence number to be removed from queue
* @return true if one element was removed, false if no element to remove was found
*/
bool remove_sn(uint32_t sn)
{
if (queue.empty()) {
return false;
}
auto iter = queue.begin();
while (iter != queue.end()) {
if (iter->sn == sn) {
iter = queue.erase(iter);
return true;
} else {
++iter;
}
}
return false;
}
};
} // namespace srsran
#endif // SRSRAN_RLC_AM_DATA_STRUCTS_H