Gw Class Reference

Network gateway component. More...

#include <Gw.h>

Inheritance diagram for Gw:

Collaboration diagram for Gw:

Public Member Functions
	Gw (const libconfig::Config &cfg, Phy &phy)
	Default constructor. More...
virtual	~Gw ()
	Default destructor. More...
void	init ()
	Creates the TUN interface according to params from Cfg. More...
void	write_pdu_mch (uint32_t mch_idx, uint32_t lcid, srsran::unique_byte_buffer_t pdu) override
	Handle a MCH PDU. More...
void	add_mch_port (uint32_t lcid, uint32_t port) override
void	write_pdu (uint32_t lcid, srsran::unique_byte_buffer_t pdu) override
int	setup_if_addr (uint32_t lcid, uint8_t pdn_type, uint32_t ip_addr, uint8_t *ipv6_if_id, char *err_str) override
int	apply_traffic_flow_template (const uint8_t &eps_bearer_id, const LIBLTE_MME_TRAFFIC_FLOW_TEMPLATE_STRUCT *tft) override
void	set_test_loop_mode (const test_loop_mode_state_t mode, const uint32_t ip_pdu_delay_ms=0) override
int	deactivate_eps_bearer (const uint32_t eps_bearer_id) override
bool	is_running () override

Private Attributes
const libconfig::Config &	_cfg
std::mutex	_wr_mutex
int32_t	_tun_fd = -1
Phy &	_phy

Detailed Description

Network gateway component.

Creates a TUN network interface, and writes the received MCH PDU contents out on it.

Definition at line 36 of file Gw.h.

Constructor & Destructor Documentation

Gw()

Gw::Gw ( const libconfig::Config &  cfg, Phy &  phy  )

inline

Default constructor.

Parameters

cfg	Config singleton reference
phy	PHY reference

Definition at line 44 of file Gw.h.

      : _cfg(cfg)
        , _phy(phy)
      {}

~Gw()

Gw::~Gw ( )

virtual

Default destructor.

Definition at line 93 of file Gw.cpp.

        {
  if (_tun_fd != -1) {
    close(_tun_fd);
  }
}

Member Function Documentation

add_mch_port()

void Gw::add_mch_port ( uint32_t  lcid, uint32_t  port  )

inlineoverride

Definition at line 66 of file Gw.h.

{};

apply_traffic_flow_template()

int Gw::apply_traffic_flow_template ( const uint8_t &  eps_bearer_id, const LIBLTE_MME_TRAFFIC_FLOW_TEMPLATE_STRUCT *  tft  )

inlineoverride

Definition at line 69 of file Gw.h.

{ return -1; };

deactivate_eps_bearer()

int Gw::deactivate_eps_bearer ( const uint32_t  eps_bearer_id )

inlineoverride

Definition at line 72 of file Gw.h.

{return 0;};

init()

void Gw::init

(

)

Creates the TUN interface according to params from Cfg.

Definition at line 99 of file Gw.cpp.

              {
  char* err_str = nullptr;
  struct ifreq ifr = {};
 
  _tun_fd = open("/dev/net/tun", O_RDWR | O_CLOEXEC);
  spdlog::info("TUN file descriptor {}", _tun_fd);
  if (0 > _tun_fd) {
    err_str = strerror(errno);
    spdlog::error("Failed to open TUN device {}", err_str);
    _tun_fd = -1;
  }
 
  std::string dev_name = "mbms_modem_tun";
  if (nullptr != std::getenv("MODEM_TUN_INTERFACE")) {
    dev_name = std::getenv("MODEM_TUN_INTERFACE");
  }
 
  memset(&ifr, 0, sizeof(ifr));
  ifr.ifr_flags = IFF_UP | IFF_TUN | IFF_NO_PI;
  strncpy(ifr.ifr_ifrn.ifrn_name, dev_name.c_str(),
          std::min(dev_name.length(), static_cast<size_t>(IFNAMSIZ - 1)));
  ifr.ifr_ifrn.ifrn_name[IFNAMSIZ - 1] = 0;
 
  if (0 > ioctl(_tun_fd, TUNSETIFF, &ifr)) {
    err_str = strerror(errno);
    spdlog::error("Failed to set TUN device name {}", err_str);
    close(_tun_fd);
    _tun_fd = -1;
  }
 
  if (0 > ioctl(_tun_fd, TUNSETPERSIST, 1)) {
    err_str = strerror(errno);
    spdlog::warn("Failed to set TUNSETPERSIST\n");
  }
}

is_running()

bool Gw::is_running ( )

inlineoverride

Definition at line 73 of file Gw.h.

{ return true; };

set_test_loop_mode()

void Gw::set_test_loop_mode ( const test_loop_mode_state_t  mode, const uint32_t  ip_pdu_delay_ms = 0  )

inlineoverride

Definition at line 70 of file Gw.h.

{};

setup_if_addr()

int Gw::setup_if_addr ( uint32_t  lcid, uint8_t  pdn_type, uint32_t  ip_addr, uint8_t *  ipv6_if_id, char *  err_str  )

inlineoverride

Definition at line 68 of file Gw.h.

{ return -1; };

write_pdu()

void Gw::write_pdu ( uint32_t  lcid, srsran::unique_byte_buffer_t  pdu  )

inlineoverride

Definition at line 67 of file Gw.h.

{};

write_pdu_mch()

void Gw::write_pdu_mch ( uint32_t  mch_idx, uint32_t  lcid, srsran::unique_byte_buffer_t  pdu  )

override

Handle a MCH PDU.

Verifies the contents start with an IP header, checks the IP header checksum and corrects it if necessary, and writes the packet out to the TUN interface.

Definition at line 36 of file Gw.cpp.

                                                                                      {
  char* err_str = nullptr;
  if (pdu->N_bytes > 2) {
    spdlog::debug("GW: RX MCH PDU ({} B), MCH idx {}. Stack latency: {} us", pdu->N_bytes, mch_idx,  pdu->get_latency_us().count());
 
    if (_tun_fd < 0) {
      spdlog::warn("TUN/TAP not up - dropping gw RX message\n");
    } else {
      auto ip_hdr = reinterpret_cast<iphdr*>(pdu->msg);
      if (ip_hdr->protocol == 17 /*UDP*/) {
        auto udp_hdr = reinterpret_cast<udphdr*>(pdu->msg + 4U * ip_hdr->ihl);
        char dest[INET6_ADDRSTRLEN] = "";   // NOLINT
        inet_ntop(AF_INET, (const void*)&ip_hdr->daddr, dest, sizeof(dest));
 
        _phy.set_dest_for_lcid(mch_idx, lcid, std::string(dest) + ":" + std::to_string(ntohs(udp_hdr->dest)));
 
        auto ptr = reinterpret_cast<uint16_t*>(ip_hdr);
        int32_t sum = 0;
        sum += *ptr++;   // ihl / version / dscp
        sum += *ptr++;   // total len
        sum += *ptr++;   // id
        sum += *ptr++;   // frag offset
        sum += *ptr++;   // ttl + protocol
        ptr++;           // skip checksum
        sum += *ptr++;   // src
        sum += *ptr++;   // src
        sum += *ptr++;   // dst
        sum += *ptr;     // dst
 
        sum = (sum >> 16) + (sum & 0xffff);
        sum += (sum >> 16);
 
        uint16_t chk = ~sum;
        if (ip_hdr->check != chk) {
          spdlog::info("Wrong IP header checksum {}, should be {}. Correcting.", ip_hdr->check, chk);
          ip_hdr->check = chk;
        }
      }
 
      _wr_mutex.lock();
      int n = write(_tun_fd, pdu->msg, pdu->N_bytes);
      _wr_mutex.unlock();
 
      if (n > 0 && (pdu->N_bytes != static_cast<uint32_t>(n))) {
        spdlog::warn("DL TUN/TAP short write");
      }
      if (n == 0) {
        spdlog::warn("DL TUN/TAP 0 write");
      }
      if (n < 0) {
        err_str = strerror(errno);
        spdlog::warn("DL TUN/TAP write error  {}", err_str);
      }
    }
  }
}

Member Data Documentation

_cfg

const libconfig::Config& Gw::_cfg

private

Definition at line 75 of file Gw.h.

_phy

Phy& Gw::_phy

private

Definition at line 79 of file Gw.h.

_tun_fd

int32_t Gw::_tun_fd = -1

private

Definition at line 78 of file Gw.h.

_wr_mutex

std::mutex Gw::_wr_mutex

private

Definition at line 77 of file Gw.h.

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The documentation for this class was generated from the following files:

• src/Gw.h
• src/Gw.cpp