sap_listener.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_LISTENER_H_
#define SAP_SAP_LISTENER_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 <functional>
#include <map>
#include <memory>
#include <string>
#include <string_view>
#include <thread>
 
#include "rtp/rtp_types.h"
 
namespace mediax::sap {
 
 
//  Time description
//     t=  (time the session is active)
//     r=* (zero or more repeat times)
//     z=* (optional time zone offset line)
 
//  Media description, if present
//     m=  (media name and transport address)
//     i=* (media title)
//     c=* (connection information -- optional if included at
//          session level)
//     b=* (zero or more bandwidth information lines)
//     k=* (obsolete)
//     a=* (zero or more media attribute lines)
enum class SdpTypeEnum {
  kProtocolVersion,
  kOriginatorSessionIdentifier,
  kSessionName,
  kSessionInformation,
  kUriOfDescription,
  kEmailAddress,
  kPhoneNumber,
  kConnectionInformation,
  kBandwidthInformation,
  kSessionAttribute,
  kTimeSessionActive,
  kMediaNameAndTransportAddress,
  kMediaTitle,
  KConnectionInformation,
  kUnknown
};
 
struct SdpMessage {
  uint32_t protocol_version;
  uint16_t hash;
  std::string session_name;
  std::string ip_address_source;
  std::string ip_address;
  uint32_t port;
  uint32_t height;
  uint32_t width;
  std::string sampling;
  uint32_t framerate;
  uint32_t bits_per_pixel;
  bool deleted = false;
  std::string sdp_text;
};
 
using SapCallback = std::function<void(sap::SdpMessage *sdp, void *data)>;
 
class SapListener {
 public:
  SapListener();
 
  ~SapListener();
 
  static SapListener &GetInstance();
 
  const std::map<std::string, ::mediax::sap::SdpMessage, std::less<>> &GetSapAnnouncements() const;
 
  bool GetSapAnnouncement(std::string_view session_name, SdpMessage **sdp_message);
 
  void RegisterSapListener(std::string_view session_name, const ::mediax::sap::SapCallback &callback, void *data);
 
  bool GetStreamInformation(std::string_view session_name, ::mediax::rtp::StreamInformation *stream_information) const;
  void Start();
 
  void Stop();
 
 private:
  static std::unique_ptr<SapListener> singleton_;
 
  static void SapListenerThread(SapListener *sap);
 
  SdpTypeEnum GetType(const std::string_view &line) const;
 
  std::map<std::string, std::string, std::less<>> ParseAttributes1(const std::string_view &line) const;
 
  std::map<std::string, std::string, std::less<>> ParseAttributes(const std::string_view &line) const;
 
  std::map<std::string, std::string, std::less<>> ParseAttributesEqual(const std::string &line) const;
 
  bool SapStore(std::array<uint8_t, mediax::rtp::kMaxUdpData> *udpdata, uint32_t size);
 
  std::map<std::string, SapCallback, std::less<>> callbacks_;
  std::map<std::string, SdpMessage, std::less<>> announcements_;
  std::array<uint8_t, mediax::rtp::kMaxUdpData> udpdata_;
  std::thread thread_;
  int sockfd_;
  struct sockaddr_in multicast_addr_;
  static bool running_;
  void *data_;
};
 
}  // namespace mediax::sap
 
#endif  // SAP_SAP_LISTENER_H_