sap_announcer.h

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//
// Copyright (c) 2025, Astute Systems PTY LTD
//
// This file is part of the VivoeX project developed by Astute Systems.
//
// Licensed under the Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)
// License. See the LICENSE file in the project root for full license details.
//
 
#ifndef SAP_SAP_ANNOUNCER_H_
#define SAP_SAP_ANNOUNCER_H_
 
#ifdef _WIN32
#include <winsock2.h>
#include <ws2tcpip.h>
#else
#include <arpa/inet.h>
#include <ifaddrs.h>
#include <netinet/in.h>
#include <sys/socket.h>
#endif
#include <stdint.h>
#include <unistd.h>
 
#include <array>
#include <map>
#include <string>
#include <thread>
#include <vector>
 
#include "rtp/rtp_types.h"
 
// The Session Announcement Protocol (SAP) and Session Description Protocol (SDP) namespace
namespace mediax::sap {
 
struct SapHeader {
 public:
  uint8_t version;
  uint8_t auth_len;
  uint16_t hash;
  uint32_t originating_source;
  SapHeader(uint8_t version, uint8_t auth_len, uint16_t hash, uint32_t originating_source)
      : version(version), auth_len(auth_len), hash(hash), originating_source(originating_source) {}
};
 
class SapAnnouncer {
 public:
  static SapAnnouncer &GetInstance();
 
  SapAnnouncer(SapAnnouncer const &) = delete;
 
  void AddSapAnnouncement(const ::mediax::rtp::StreamInformation &stream_information);
 
  ::mediax::rtp::StreamInformation &GetSapAnnouncment(std::string_view session_name,
                                                      std::string_view multicast_address = "");
 
  void DeleteSapAnnouncement(std::string_view session_name, std::string_view multicast_address = "");
 
  void UndeleteSapAnnouncement(std::string_view session_name);
 
  void DeleteAllSapAnnouncements();
 
  void Start();
 
  void Stop();
 
  void Restart();
 
  bool Active() const;
 
  void SetSourceInterface(uint32_t select = 0);
 
  std::map<uint32_t, std::string> GetInterfaces() const;
 
  std::vector<::mediax::rtp::StreamInformation> &GetStreams();
 
  uint32_t GetActiveStreamCount() const;
 
 private:
  SapAnnouncer();
 
  ~SapAnnouncer();
 
  static void SapAnnouncementThread(SapAnnouncer *stream_information);
 
  void SendSapAnnouncement(const ::mediax::rtp::StreamInformation &stream_information) const;
 
  void SendSapDeletion(const ::mediax::rtp::StreamInformation &stream_information) const;
 
  int SendSapPacket(const ::mediax::rtp::StreamInformation &stream_information, bool deletion) const;
 
  void DeleteAllStreams() const;
 
  uint32_t GetIpv4Address(std::string_view interface_name) const;
 
  std::string GetIpv4AddressString(std::string_view interface_name) const;
 
  static SapAnnouncer singleton_;
  std::vector<::mediax::rtp::StreamInformation> streams_;
  std::thread thread_;
  uint32_t source_ipaddress_;
  int sockfd_;
  struct sockaddr_in multicast_addr_;
  bool running_ = false;
};
 
}  // namespace mediax::sap
 
#endif  // SAP_SAP_ANNOUNCER_H_