FLUTE receiver class. More...

#include <Receiver.h>

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

Public Member Functions
	Receiver (const std::string &iface, const std::string &address, short port, uint64_t tsi, boost::asio::io_context &io_context, const std::string &source_address="")
	Default constructor. More...

virtual	~Receiver ()
	Destructor. More...

void	enable_ipsec (uint32_t spi, const std::string &aes_key)
	Enable IPSEC ESP decryption of FLUTE payloads. More...

std::vector< std::shared_ptr< LibFlute::File > >	file_list ()
	List all current files. More...

void	remove_expired_files (unsigned max_age)
	Remove files from the list that are older than max_age seconds. More...

void	remove_file_with_content_location (const std::string &cl)
	Remove a file from the list that matches the passed content location. More...

void	register_completion_callback (completion_callback_t cb)
	Register a callback for file reception notifications. More...

void	stop ()

Detailed Description

FLUTE receiver class.

Construct an instance of this to receive files from a FLUTE/ALC session.

Definition at line 31 of file Receiver.h.

Member Typedef Documentation

◆ completion_callback_t

typedef std::function<void(std::shared_ptr<LibFlute::File>)> LibFlute::Receiver::completion_callback_t

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

Returns: shared_ptr to the received file

Definition at line 39 of file Receiver.h.

Constructor & Destructor Documentation

◆ Receiver()

LibFlute::Receiver::Receiver	(	const std::string &	iface,
		const std::string &	address,
		short	port,
		uint64_t	tsi,
		boost::asio::io_context &	io_context,
		const std::string &	source_address = `""`
	)

Default constructor.

Parameters

iface	Address of the (local) interface to bind the receiving socket to. 0.0.0.0 = any.
address	Multicast address
port	Target port
tsi	TSI value of the session
io_context	Boost io_context to run the socket operations in (must be provided by the caller)
source_address	If non-empty, join as source-specific multicast (SSM, IPv4 only) admitting only packets from this source – otherwise ASM (any-source).

Definition at line 68 of file Receiver.cpp.

     : _socket(io_context)
     , _tsi(tsi)
     , _mcast_address(address)
 {
     // Restored alongside the ANY-bind/specific-interface-join fixes below:
     // an earlier version of those fixes made this whole constructor IPv4
     // only, where the original code let Boost pick v4 vs v6 based on the
     // address types passed in. `address`'s family (not `iface`'s -- iface
     // can legitimately be "0.0.0.0"/"::"/empty, meaning "any") is the
     // authoritative signal for which family this session actually uses.
     auto mcast_address = boost::asio::ip::make_address(address);
     bool is_v6 = mcast_address.is_v6();
  
     // Bind to ANY, not the specific interface address: incoming multicast
     // packets are addressed to the group, not to a particular unicast
     // interface address, so binding to that unicast address is non-standard
     // - and in practice it also breaks epoll-based readiness notification
     // for this socket (confirmed directly: async_receive_from never
     // completes when bound to a specific interface address, even though the
     // data really does arrive and a plain synchronous recv() picks it up;
     // binding to ANY fixes it). `iface` is still used below to select which
     // interface's multicast membership to join.
     boost::asio::ip::udp::endpoint listen_endpoint(
         is_v6 ? boost::asio::ip::address(boost::asio::ip::address_v6::any())
               : boost::asio::ip::address(boost::asio::ip::address_v4::any()),
         port);
     _socket.open(listen_endpoint.protocol());
     _socket.set_option(boost::asio::ip::multicast::enable_loopback(true));
     _socket.set_option(boost::asio::ip::udp::socket::reuse_address(true));
     _socket.set_option(boost::asio::socket_base::receive_buffer_size(16*1024*1024));
     _socket.bind(listen_endpoint);
  
     if (!source_address.empty()) {
       // Source-specific multicast (SSM, RFC 4607): admits only packets from source_address,
       // as indicated by an SDP a=source-filter line (RFC 4570; TS 26.517 cl.6.2.2.3's own
       // examples use this for FLUTE sessions). boost::asio has no portable SSM join, so this
       // goes straight to the socket options Linux (and most other stacks) actually define --
       // IPv4's ip_mreq_source/IP_ADD_SOURCE_MEMBERSHIP identifies the interface by address;
       // IPv6's group_source_req/MCAST_JOIN_SOURCE_GROUP identifies it by index instead
       // (see resolve_iface_index() above), which is why the two branches build genuinely
       // different structures rather than sharing one.
       if (is_v6) {
         struct group_source_req gsr{};
         gsr.gsr_interface = resolve_iface_index(iface);
  
         struct sockaddr_in6 grp{};
         grp.sin6_family = AF_INET6;
         auto mcast_bytes = mcast_address.to_v6().to_bytes();
         std::memcpy(&grp.sin6_addr, mcast_bytes.data(), mcast_bytes.size());
         std::memcpy(&gsr.gsr_group, &grp, sizeof(grp));
  
         struct sockaddr_in6 src{};
         src.sin6_family = AF_INET6;
         auto src_bytes = boost::asio::ip::make_address(source_address).to_v6().to_bytes();
         std::memcpy(&src.sin6_addr, src_bytes.data(), src_bytes.size());
         std::memcpy(&gsr.gsr_source, &src, sizeof(src));
  
         if (setsockopt(_socket.native_handle(), IPPROTO_IPV6, MCAST_JOIN_SOURCE_GROUP,
                         &gsr, sizeof(gsr)) != 0) {
           spdlog::error("Receiver: MCAST_JOIN_SOURCE_GROUP for {} from {} failed: {}", address,
                         source_address, strerror(errno));
         } else {
           spdlog::info("Receiver: joined SSM {} from source {} on iface {}", address,
                        source_address, iface);
         }
       } else {
         struct ip_mreq_source mreq_source{};
         auto mcast_bytes = mcast_address.to_v4().to_bytes();
         auto src_bytes = boost::asio::ip::make_address(source_address).to_v4().to_bytes();
         auto iface_bytes = boost::asio::ip::make_address(iface).to_v4().to_bytes();
         std::memcpy(&mreq_source.imr_multiaddr, mcast_bytes.data(), mcast_bytes.size());
         std::memcpy(&mreq_source.imr_sourceaddr, src_bytes.data(), src_bytes.size());
         std::memcpy(&mreq_source.imr_interface, iface_bytes.data(), iface_bytes.size());
  
         if (setsockopt(_socket.native_handle(), IPPROTO_IP, IP_ADD_SOURCE_MEMBERSHIP,
                         &mreq_source, sizeof(mreq_source)) != 0) {
           spdlog::error("Receiver: IP_ADD_SOURCE_MEMBERSHIP for {} from {} failed: {}", address,
                         source_address, strerror(errno));
         } else {
           spdlog::info("Receiver: joined SSM {} from source {} on iface {}", address,
                        source_address, iface);
         }
       }
     } else if (is_v6) {
       // Plain (any-source) multicast join, IPv6: join_group(address_v6, interface_index) --
       // a different overload shape than IPv4's join_group(address_v4, address_v4) below,
       // since v6 identifies the interface by index (see resolve_iface_index()).
       _socket.set_option(
           boost::asio::ip::multicast::join_group(
             mcast_address.to_v6(), resolve_iface_index(iface)));
     } else {
       // Join the multicast group on the specific interface passed in - the
       // single-address join_group() overload ignores `iface` entirely and
       // joins via whatever interface the system considers the default route
       // for the group, which silently breaks reception when the content
       // actually arrives on a non-default interface (e.g. the modem's own
       // TUN device rather than a physical NIC).
       _socket.set_option(
           boost::asio::ip::multicast::join_group(
             mcast_address.to_v4(),
             boost::asio::ip::make_address(iface).to_v4()));
     }
  
     arm_receive();
 }

◆ ~Receiver()

LibFlute::Receiver::~Receiver ( )

virtual

Destructor.

Marks the receiver as no longer alive so that any async_receive_from completion already queued on the io_context when this object is destroyed (e.g. the owner recreated the receiver, or a caller destroys it mid-flight) finds out before touching a freed this – boost::asio only guarantees a cancelled operation's handler eventually runs with operation_aborted, not that it runs before the destructor returns, so a raw this-bound handler left queued past that point would otherwise be a use-after-free.

Definition at line 178 of file Receiver.cpp.

 {
   *_alive = false;
 }

Member Function Documentation

◆ enable_ipsec()

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

Enable IPSEC ESP decryption 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 194 of file Receiver.cpp.

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

◆ file_list()

auto LibFlute::Receiver::file_list ( )

List all current files.

Returns: Vector of all files currently in the FDT

Definition at line 328 of file Receiver.cpp.

 {
   std::vector<std::shared_ptr<LibFlute::File>> files;
   for (auto& f : _files) {
     files.push_back(f.second);
   }
   return files;
 }

◆ register_completion_callback()

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

inline

Register a callback for file reception notifications.

Parameters

cb	Function to call on file completion

Definition at line 97 of file Receiver.h.

97 { _completion_cb = cb; };

◆ remove_expired_files()

auto LibFlute::Receiver::remove_expired_files ( unsigned max_age )

Remove files from the list that are older than max_age seconds.

Definition at line 337 of file Receiver.cpp.

 {
   const std::lock_guard<std::mutex> lock(_files_mutex);
   for (auto it = _files.cbegin(); it != _files.cend();)
   {
     auto age = time(nullptr) - it->second->received_at();
     if ( it->second->meta().content_location != "bootstrap.multipart"  && age > max_age) {
       it = _files.erase(it);
     } else {
       ++it;
     }
   }
 }

◆ remove_file_with_content_location()

auto LibFlute::Receiver::remove_file_with_content_location ( const std::string & cl )

Remove a file from the list that matches the passed content location.

Definition at line 351 of file Receiver.cpp.

 {
   const std::lock_guard<std::mutex> lock(_files_mutex);
   for (auto it = _files.cbegin(); it != _files.cend();)
   {
     if ( it->second->meta().content_location == cl) {
       it = _files.erase(it);
     } else {
       ++it;
     }
   }
 }

◆ stop()

void LibFlute::Receiver::stop ( )

inline

Definition at line 99 of file Receiver.h.

99 { _running = false; }

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

include/Receiver.h
src/Receiver.cpp

Public Types

Public Member Functions

Detailed Description

Member Typedef Documentation

◆ completion_callback_t

Constructor & Destructor Documentation

◆ Receiver()

◆ ~Receiver()

Member Function Documentation

◆ enable_ipsec()

◆ file_list()

◆ register_completion_callback()

◆ remove_expired_files()

◆ remove_file_with_content_location()

◆ stop()