LibFlute::Transmitter Class Reference

FLUTE transmitter class. More...

#include <Transmitter.h>

Public Types
typedef std::function< void(uint32_t)>	completion_callback_t
	Definition of a file transmission completion callback function that can be registered through ::register_completion_callback. More...

Public Member Functions
	Transmitter (const std::string &address, short port, uint64_t tsi, unsigned short mtu, uint32_t rate_limit, boost::asio::io_service &io_service)
	Default constructor. More...
virtual	~Transmitter ()
	Default destructor. More...
void	enable_ipsec (uint32_t spi, const std::string &aes_key)
	Enable IPSEC ESP encryption of FLUTE payloads. More...
uint16_t	send (const std::string &content_location, const std::string &content_type, uint32_t expires, char *data, size_t length)
	Transmit a file. More...
uint64_t	seconds_since_epoch ()
	Convenience function to get the current timestamp for expiry calculation. More...
void	register_completion_callback (completion_callback_t cb)
	Register a callback for file transmission completion notifications. More...

Detailed Description

FLUTE transmitter class.

Construct an instance of this to send data through a FLUTE/ALC session.

Definition at line 34 of file Transmitter.h.

Member Typedef Documentation

completion_callback_t

typedef std::function<void(uint32_t)> LibFlute::Transmitter::completion_callback_t

Definition of a file transmission completion callback function that can be registered through ::register_completion_callback.

Parameters

toi	TOI of the file that has completed transmission

Definition at line 42 of file Transmitter.h.

Constructor & Destructor Documentation

Transmitter()

LibFlute::Transmitter::Transmitter	(	const std::string &	address,
		short	port,
		uint64_t	tsi,
		unsigned short	mtu,
		uint32_t	rate_limit,
		boost::asio::io_service &	io_service
	)

Default constructor.

Parameters

address	Target multicast address
port	Target port
tsi	TSI value for the session
mtu	Path MTU to size FLUTE packets for
rate_limit	Transmit rate limit (in kbps)
io_service	Boost io_service to run the socket operations in (must be provided by the caller)

Definition at line 26 of file Transmitter.cpp.

    : _endpoint(boost::asio::ip::address::from_string(address), port)
    , _socket(io_service, _endpoint.protocol())
    , _fdt_timer(io_service)
    , _send_timer(io_service)
    , _io_service(io_service)
    , _tsi(tsi)
    , _mtu(mtu)
    , _rate_limit(rate_limit)
    , _mcast_address(address)
{
  _max_payload = mtu -
    20 - // IPv4 header
     8 - // UDP header
    32 - // ALC Header with EXT_FDT and EXT_FTI
     4;  // SBN and ESI for compact no-code FEC
  uint32_t max_source_block_length = 64;
 
  _socket.set_option(boost::asio::ip::multicast::enable_loopback(true));
  _socket.set_option(boost::asio::ip::udp::socket::reuse_address(true));
 
  _fec_oti = FecOti{FecScheme::CompactNoCode, 0, _max_payload, max_source_block_length};
  _fdt = std::make_unique<FileDeliveryTable>(1, _fec_oti);
 
  _fdt_timer.expires_from_now(boost::posix_time::seconds(_fdt_repeat_interval));
  _fdt_timer.async_wait( boost::bind(&Transmitter::fdt_send_tick, this));
 
  send_next_packet();
}

~Transmitter()

LibFlute::Transmitter::~Transmitter ( )

virtualdefault

Default destructor.

Member Function Documentation

enable_ipsec()

auto LibFlute::Transmitter::enable_ipsec	(	uint32_t	spi,
		const std::string &	aes_key
	)

Enable IPSEC ESP encryption of FLUTE payloads.

Parameters

spi	Security Parameter Index value to use
key	AES key as a hex string (without leading 0x). Must be an even number of characters long.

Definition at line 60 of file Transmitter.cpp.

{
  LibFlute::IpSec::enable_esp(spi, _mcast_address, LibFlute::IpSec::Direction::Out, key);
}

register_completion_callback()

void LibFlute::Transmitter::register_completion_callback ( completion_callback_t  cb )

inline

Register a callback for file transmission completion notifications.

Parameters

cb	Function to call on file completion

Definition at line 103 of file Transmitter.h.

{ _completion_cb = cb; };

seconds_since_epoch()

auto LibFlute::Transmitter::seconds_since_epoch

(

)

Convenience function to get the current timestamp for expiry calculation.

Returns

seconds since the NTP epoch

Definition at line 71 of file Transmitter.cpp.

{
  return std::chrono::duration_cast<std::chrono::seconds>(
      std::chrono::system_clock::now().time_since_epoch()).count();
}

send()

auto LibFlute::Transmitter::send	(	const std::string &	content_location,
		const std::string &	content_type,
		uint32_t	expires,
		char *	data,
		size_t	length
	)

Transmit a file.

The caller must ensure the data buffer passed here remains valid until the completion callback for this file is called.

Parameters

content_location	URI to set in the content location field of the generated FDT entry
content_type	MIME type to set in the content type field of the generated FDT entry
expires	Expiry timestamp (based on NTP epoch)
data	Pointer to the data buffer (managed by caller)
length	Length of the data buffer (in bytes)

Returns

TOI of the file

Definition at line 93 of file Transmitter.cpp.

{
  auto toi = _toi;
  _toi++;
  if (_toi == 0) _toi = 1; // clamp to >= 1 in case it wraps
 
  auto file = std::make_shared<File>(
        toi,
        _fec_oti,
        content_location,
        content_type,
        expires,
        data,
        length);
 
  _fdt->add(file->meta());
  send_fdt();
  _files.insert({toi, file});
  return toi;
}

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

• include/Transmitter.h
• src/Transmitter.cpp