srsRAN_4G/lib/src/common/mac_pcap.cc

/**
 *
 * \section COPYRIGHT
 *
 * Copyright 2013-2020 Software Radio Systems Limited
 *
 * By using this file, you agree to the terms and conditions set
 * forth in the LICENSE file which can be found at the top level of
 * the distribution.
 *
 */

#include "srslte/common/mac_pcap.h"
#include "srslte/config.h"
#include "srslte/phy/common/phy_common.h"
#include <stdint.h>

namespace srslte {

mac_pcap::mac_pcap() :
  pool(srslte::byte_buffer_pool::get_instance()), log(srslte::logmap::get("MAC")), thread("PCAP_WRITER")
{}

mac_pcap::~mac_pcap()
{
  close();
}

void mac_pcap::enable(bool enable_)
{
  std::lock_guard<std::mutex> lock(mutex);
  running = enable_;
}

uint32_t mac_pcap::open(const char* filename, uint32_t ue_id_)
{
  std::lock_guard<std::mutex> lock(mutex);
  if (pcap_file != nullptr) {
    log->error("PCAP writer already running. Close first.\n");
    return SRSLTE_ERROR;
  }

  pcap_file = LTE_PCAP_Open(MAC_LTE_DLT, filename);
  if (pcap_file == nullptr) {
    log->error("Couldn't open file to write PCAP\n");
    return SRSLTE_ERROR;
  }

  ue_id   = ue_id_;
  running = true;

  // start writer thread
  start();

  return SRSLTE_SUCCESS;
}

uint32_t mac_pcap::close()
{
  {
    std::lock_guard<std::mutex> lock(mutex);
    if (running == false || pcap_file == nullptr) {
      return SRSLTE_ERROR;
    }

    // tell writer thread to stop
    running        = false;
    pcap_pdu_t pdu = {};
    queue.push(std::move(pdu));
  }

  wait_thread_finish();

  // close file handle
  {
    std::lock_guard<std::mutex> lock(mutex);
    srslte::console("Saving MAC PCAP file\n");
    LTE_PCAP_Close(pcap_file);
    pcap_file = nullptr;
  }

  return SRSLTE_SUCCESS;
}

void mac_pcap::write_pdu(pcap_pdu_t& pdu)
{
  if (pdu.pdu != nullptr) {
    LTE_PCAP_MAC_WritePDU(pcap_file, &pdu.context, pdu.pdu->msg, pdu.pdu->N_bytes);
  }
}

void mac_pcap::run_thread()
{
  // blocking write until stopped
  while (running) {
    pcap_pdu_t pdu = queue.wait_pop();
    {
      std::lock_guard<std::mutex> lock(mutex);
      write_pdu(pdu);
    }
  }

  // write remainder of queue
  std::lock_guard<std::mutex> lock(mutex);
  pcap_pdu_t                  pdu = {};
  while (queue.try_pop(&pdu)) {
    write_pdu(pdu);
  }
}

void mac_pcap::set_ue_id(uint16_t ue_id_)
{
  std::lock_guard<std::mutex> lock(mutex);
  ue_id = ue_id_;
}

// Function called from PHY worker context, locking not needed as PDU queue is thread-safe
void mac_pcap::pack_and_queue(uint8_t* payload,
                              uint32_t payload_len,
                              uint32_t reTX,
                              bool     crc_ok,
                              uint8_t  cc_idx,
                              uint32_t tti,
                              uint16_t crnti,
                              uint8_t  direction,
                              uint8_t  rnti_type)
{
  if (running && payload != nullptr) {
    pcap_pdu_t pdu             = {};
    pdu.context.radioType      = FDD_RADIO;
    pdu.context.direction      = direction;
    pdu.context.rntiType       = rnti_type;
    pdu.context.rnti           = crnti;
    pdu.context.ueid           = (uint16_t)ue_id;
    pdu.context.isRetx         = (uint8_t)reTX;
    pdu.context.crcStatusOK    = crc_ok;
    pdu.context.cc_idx         = cc_idx;
    pdu.context.sysFrameNumber = (uint16_t)(tti / 10);
    pdu.context.subFrameNumber = (uint16_t)(tti % 10);

    // try to allocate PDU buffer
    pdu.pdu = srslte::allocate_unique_buffer(*pool);
    if (pdu.pdu != nullptr && pdu.pdu->get_tailroom() >= payload_len) {
      // copy payload into PDU buffer
      memcpy(pdu.pdu->msg, payload, payload_len);
      pdu.pdu->N_bytes = payload_len;
      queue.push(std::move(pdu));
    } else {
      log->info("Dropping PDU in PCAP. No buffer available or not enough space (pdu_len=%d).\n", payload_len);
    }
  }
}

void mac_pcap::write_dl_crnti(uint8_t* pdu,
                              uint32_t pdu_len_bytes,
                              uint16_t rnti,
                              bool     crc_ok,
                              uint32_t tti,
                              uint8_t  cc_idx)
{
  pack_and_queue(pdu, pdu_len_bytes, 0, crc_ok, cc_idx, tti, rnti, DIRECTION_DOWNLINK, C_RNTI);
}
void mac_pcap::write_dl_ranti(uint8_t* pdu,
                              uint32_t pdu_len_bytes,
                              uint16_t rnti,
                              bool     crc_ok,
                              uint32_t tti,
                              uint8_t  cc_idx)
{
  pack_and_queue(pdu, pdu_len_bytes, 0, crc_ok, cc_idx, tti, rnti, DIRECTION_DOWNLINK, RA_RNTI);
}
void mac_pcap::write_ul_crnti(uint8_t* pdu,
                              uint32_t pdu_len_bytes,
                              uint16_t rnti,
                              uint32_t reTX,
                              uint32_t tti,
                              uint8_t  cc_idx)
{
  pack_and_queue(pdu, pdu_len_bytes, reTX, true, cc_idx, tti, rnti, DIRECTION_UPLINK, C_RNTI);
}

void mac_pcap::write_sl_crnti(uint8_t* pdu,
                              uint32_t pdu_len_bytes,
                              uint16_t rnti,
                              uint32_t reTX,
                              uint32_t tti,
                              uint8_t  cc_idx)
{
  pack_and_queue(pdu, pdu_len_bytes, reTX, true, cc_idx, tti, rnti, DIRECTION_UPLINK, SL_RNTI);
}

void mac_pcap::write_dl_bch(uint8_t* pdu, uint32_t pdu_len_bytes, bool crc_ok, uint32_t tti, uint8_t cc_idx)
{
  pack_and_queue(pdu, pdu_len_bytes, 0, crc_ok, cc_idx, tti, 0, DIRECTION_DOWNLINK, NO_RNTI);
}
void mac_pcap::write_dl_pch(uint8_t* pdu, uint32_t pdu_len_bytes, bool crc_ok, uint32_t tti, uint8_t cc_idx)
{
  pack_and_queue(pdu, pdu_len_bytes, 0, crc_ok, cc_idx, tti, SRSLTE_PRNTI, DIRECTION_DOWNLINK, P_RNTI);
}
void mac_pcap::write_dl_mch(uint8_t* pdu, uint32_t pdu_len_bytes, bool crc_ok, uint32_t tti, uint8_t cc_idx)
{
  pack_and_queue(pdu, pdu_len_bytes, 0, crc_ok, cc_idx, tti, SRSLTE_MRNTI, DIRECTION_DOWNLINK, M_RNTI);
}
void mac_pcap::write_dl_sirnti(uint8_t* pdu, uint32_t pdu_len_bytes, bool crc_ok, uint32_t tti, uint8_t cc_idx)
{
  pack_and_queue(pdu, pdu_len_bytes, 0, crc_ok, cc_idx, tti, SRSLTE_SIRNTI, DIRECTION_DOWNLINK, SI_RNTI);
}

void mac_pcap::write_ul_rrc_pdu(const uint8_t* input, const int32_t input_len)
{
  uint8_t pdu[1024];
  bzero(pdu, sizeof(pdu));

  // Size is limited by PDU buffer and MAC subheader (format 1 < 128 B)
  if (input_len > 128 - 7) {
    log->error("PDU too large.\n");
    return;
  }

  //  MAC PDU Header (Short BSR) (1:54) (Padding:remainder)  [3 subheaders]
  //  Sub-header (lcid=Short BSR)
  //      0... .... = SCH reserved bit: 0x0
  //      .0.. .... = Format2: Data length is < 32768 bytes
  //      ..1. .... = Extension: 0x1
  //      ...1 1101 = LCID: Short BSR (0x1d)
  //  Sub-header (lcid=1, length=54)
  //      0... .... = SCH reserved bit: 0x0
  //      .0.. .... = Format2: Data length is < 32768 bytes
  //      ..1. .... = Extension: 0x1
  //      ...0 0001 = LCID: 1 (0x01)
  //      0... .... = Format: Data length is < 128 bytes
  //      .011 0110 = Length: 54 (Will be dynamically updated)
  //  Sub-header (lcid=Padding, length is remainder)
  //      0... .... = SCH reserved bit: 0x0
  //      .0.. .... = Format2: Data length is < 32768 bytes
  //      ..0. .... = Extension: 0x0
  //      ...1 1111 = LCID: Padding (0x1f)
  uint8_t mac_hdr[] = {0x3D, 0x21, 0x36, 0x1F, 0x0C};

  // Update MAC length
  mac_hdr[2] = input_len + 7; // rlc_hdr (2) + pdcp_hdr (1) + MAC (4)

  //  AM Header  (P) sn=4
  //  1... .... = Frame type: Data PDU (0x1)
  //  .0.. .... = Re-segmentation Flag: AMD PDU (0x0)
  //  ..1. .... = Polling Bit: Status report is requested (0x1)
  //  ...0 0... = Framing Info: First byte begins a RLC SDU and last byte ends a RLC SDU (0x0)
  //  .... .0.. = Extension: Data field follows from the octet following the fixed part of the header (0x0)
  //  .... ..00 0000 0100 = Sequence Number: 4
  uint8_t rlc_hdr[] = {0xA0, 0x04};

  //  PDCP-LTE sn=3
  //  000. .... = Reserved: 0
  //  ...0 0011 = Seq Num: 3
  uint8_t pdcp_hdr[] = {0x03};

  uint8_t* pdu_ptr = pdu;

  memcpy(pdu_ptr, mac_hdr, sizeof(mac_hdr));
  pdu_ptr += sizeof(mac_hdr);
  memcpy(pdu_ptr, rlc_hdr, sizeof(rlc_hdr));
  pdu_ptr += sizeof(rlc_hdr);
  memcpy(pdu_ptr, pdcp_hdr, sizeof(pdcp_hdr));
  pdu_ptr += sizeof(pdcp_hdr);
  memcpy(pdu_ptr, input, input_len);
  pdu_ptr += input_len;

  // MAC
  uint8_t pad = 0x00;
  for (uint32_t i = 0; i < 4; i++) {
    memcpy(pdu_ptr, &pad, 1);
    pdu_ptr += 1;
  }

  // Pad
  memcpy(pdu_ptr, &pad, 1);
  pdu_ptr += 1;

  write_ul_crnti(pdu, pdu_ptr - pdu, 14931, true, 0, 0);
}
} // namespace srslte