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/**
* Copyright 2013-2023 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_GTPU_H
#define SRSRAN_GTPU_H
#include "srsran/common/byte_buffer.h"
#include "srsran/common/common.h"
#include "srsran/srslog/srslog.h"
#include <stdint.h>
namespace srsran {
/****************************************************************************
* GTPU Header
* Ref: 3GPP TS 29.281 v10.1.0 Section 5
*
* | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 |
*
* 1 | Version |PT | * | E | S |PN |
* 2 | Message Type |
* 3 | Length (1st Octet) |
* 4 | Length (2nd Octet) |
* 5 | TEID (1st Octet) |
* 6 | TEID (2nd Octet) |
* 7 | TEID (3rd Octet) |
* 8 | TEID (4th Octet) |
* 9 | Seq Number (1st Octet) |
* 10 | Seq Number (2st Octet) |
* 11 | N-PDU |
* 12 | Next Extension Header Type |
***************************************************************************/
#define GTPU_BASE_HEADER_LEN 8
#define GTPU_EXTENDED_HEADER_LEN 12
#define GTPU_FLAGS_VERSION_MASK 0xE0
#define GTPU_FLAGS_VERSION_V1 0x20
#define GTPU_FLAGS_GTP_PRIME_PROTOCOL 0x00
#define GTPU_FLAGS_GTP_PROTOCOL 0x10
#define GTPU_FLAGS_EXTENDED_HDR 0x04
#define GTPU_FLAGS_SEQUENCE 0x02
#define GTPU_FLAGS_PACKET_NUM 0x01
#define GTPU_MSG_ECHO_REQUEST 1
#define GTPU_MSG_ECHO_RESPONSE 2
#define GTPU_MSG_ERROR_INDICATION 26
#define GTPU_MSG_SUPPORTED_EXTENSION_HEADERS_NOTIFICATION 31
#define GTPU_MSG_END_MARKER 254
#define GTPU_MSG_DATA_PDU 255
#define GTPU_EXT_NO_MORE_EXTENSION_HEADERS 0x00
#define GTPU_EXT_HEADER_PDCP_PDU_NUMBER 0b11000000
#define GTPU_EXT_HEADER_PDU_SESSION_CONTAINER 0x85
#define GTPU_EXT_HEADER_PDU_SESSION_CONTAINER_LEN 4
struct gtpu_header_t {
uint8_t flags = 0;
uint8_t message_type = 0;
uint16_t length = 0;
uint32_t teid = 0;
uint16_t seq_number = 0;
uint8_t n_pdu = 0;
uint8_t next_ext_hdr_type = 0;
std::vector<uint8_t> ext_buffer;
};
bool gtpu_read_header(srsran::byte_buffer_t* pdu, gtpu_header_t* header, srslog::basic_logger& logger);
bool gtpu_write_header(gtpu_header_t* header, srsran::byte_buffer_t* pdu, srslog::basic_logger& logger);
void gtpu_ntoa(fmt::memory_buffer& buffer, uint32_t addr);
inline bool gtpu_supported_flags_check(gtpu_header_t* header, srslog::basic_logger& logger)
{
// flags
if ((header->flags & GTPU_FLAGS_VERSION_MASK) != GTPU_FLAGS_VERSION_V1) {
logger.error("gtpu_header - Unhandled GTP-U Version. Flags: 0x%x", header->flags);
return false;
}
if (!(header->flags & GTPU_FLAGS_GTP_PROTOCOL)) {
logger.error("gtpu_header - Unhandled Protocol Type. Flags: 0x%x", header->flags);
return false;
}
if (header->flags & GTPU_FLAGS_PACKET_NUM) {
logger.error("gtpu_header - Unhandled Packet Number. Flags: 0x%x", header->flags);
return false;
}
return true;
}
inline bool gtpu_supported_msg_type_check(gtpu_header_t* header, srslog::basic_logger& logger)
{
// msg_tpye
if (header->message_type != GTPU_MSG_DATA_PDU && header->message_type != GTPU_MSG_ECHO_REQUEST &&
header->message_type != GTPU_MSG_ECHO_RESPONSE && header->message_type != GTPU_MSG_ERROR_INDICATION &&
header->message_type != GTPU_MSG_END_MARKER) {
logger.error("gtpu_header - Unhandled message type: 0x%x", header->message_type);
return false;
}
return true;
}
} // namespace srsran
#endif