srsRAN_4G/lib/src/common/mac_pcap.cc

/*
 * 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/.
 *
 */

#include <stdint.h>
#include "srslte/srslte.h"
#include "srslte/common/pcap.h"
#include "srslte/common/mac_pcap.h"

namespace srslte {

mac_pcap::mac_pcap() : enable_write(false), ue_id(0), pcap_file(nullptr) {}

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

void mac_pcap::enable(bool en)
{
  enable_write = true; 
}
void mac_pcap::open(const char* filename, uint32_t ue_id)
{
  pcap_file = LTE_PCAP_Open(MAC_LTE_DLT, filename);
  this->ue_id = ue_id;
  enable_write = true;
}
void mac_pcap::close()
{
  enable_write = false;
  if (pcap_file != nullptr) {
    fprintf(stdout, "Saving MAC PCAP file\n");
    LTE_PCAP_Close(pcap_file);
    pcap_file = nullptr;
  }
}

void mac_pcap::set_ue_id(uint16_t ue_id) {
  this->ue_id = ue_id;
}

void mac_pcap::pack_and_write(uint8_t* pdu, uint32_t pdu_len_bytes, uint32_t reTX, bool crc_ok, uint32_t tti, 
                              uint16_t crnti, uint8_t direction, uint8_t rnti_type)
{
  if (enable_write) {
    MAC_Context_Info_t  context =
    {
        FDD_RADIO, direction, rnti_type,
        crnti,       /* RNTI */
        (uint16_t)ue_id,      /* UEId */
        (uint8_t)reTX,        /* Retx */
        crc_ok,        /* CRC Stsatus (i.e. OK) */
        (uint16_t)(tti/10),        /* Sysframe number */
        (uint16_t)(tti%10)        /* Subframe number */
    };
    if (pdu) {
      LTE_PCAP_MAC_WritePDU(pcap_file, &context, pdu, pdu_len_bytes);
    }
  }
}

void mac_pcap::write_dl_crnti(uint8_t* pdu, uint32_t pdu_len_bytes, uint16_t rnti, bool crc_ok, uint32_t tti)
{
  pack_and_write(pdu, pdu_len_bytes, 0, crc_ok, 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)
{
  pack_and_write(pdu, pdu_len_bytes, 0, crc_ok, 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)
{
  pack_and_write(pdu, pdu_len_bytes, reTX, true, tti, rnti, DIRECTION_UPLINK, C_RNTI);
}
void mac_pcap::write_dl_bch(uint8_t* pdu, uint32_t pdu_len_bytes, bool crc_ok, uint32_t tti)
{
  pack_and_write(pdu, pdu_len_bytes, 0, crc_ok, 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)
{
  pack_and_write(pdu, pdu_len_bytes, 0, crc_ok, 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)
{
  pack_and_write(pdu, pdu_len_bytes, 0, crc_ok, 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)
{
  pack_and_write(pdu, pdu_len_bytes, 0, crc_ok, 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) {
    printf("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);
}
}