[feat] SSRC supported for RTP packets

src/rtp/rtp_packet/rtp_codec.cpp

@@ -1,6 +1,7 @@
 #include "rtp_codec.h"
 
 #include <chrono>
+#include <random>
 
 #include "log.h"
 #include "obu_parser.h"
@@ -14,16 +15,35 @@ constexpr int kObuTypeSequenceHeader = 1;
 
 using namespace obu;
 
+uint32_t GenerateRandomSSRC() {
+  std::random_device rd;
+  std::mt19937 gen(rd());
+  std::uniform_int_distribution<uint32_t> dis(1, 0xFFFFFFFF);
+  return dis(gen);
+}
+
+uint32_t GenerateUniqueSsrc() {
+  uint32_t new_ssrc;
+  do {
+    new_ssrc = GenerateRandomSSRC();
+  } while (SSRCManager::Instance().Contains(new_ssrc));
+  SSRCManager::Instance().AddSsrc(new_ssrc);
+  return new_ssrc;
+}
+
 RtpCodec ::RtpCodec(RtpPacket::PAYLOAD_TYPE payload_type)
     : version_(RTP_VERSION),
       has_padding_(false),
       has_extension_(false),
       payload_type_(payload_type),
       sequence_number_(1) {
+  ssrc_ = GenerateUniqueSsrc();
   fec_encoder_.Init();
 }
 
 RtpCodec ::~RtpCodec() {
+  SSRCManager::Instance().DeleteSsrc(ssrc_);
+
   if (extension_data_) {
     delete extension_data_;
     extension_data_ = nullptr;

src/rtp/rtp_packet/rtp_codec.h

@@ -3,6 +3,7 @@
 
 #include <cstddef>
 #include <cstdint>
+#include <unordered_set>
 #include <vector>
 
 #include "fec_encoder.h"
@@ -57,4 +58,36 @@ class RtpCodec {
   FecEncoder fec_encoder_;
 };
 
+class SSRCManager {
+ public:
+  static SSRCManager& Instance() {
+    static SSRCManager instance;
+    return instance;
+  }
+
+  void AddSsrc(uint32_t ssrc) {
+    std::lock_guard<std::mutex> lock(mutex_);
+    ssrcs_.insert(ssrc);
+  }
+
+  void DeleteSsrc(uint32_t ssrc) {
+    std::lock_guard<std::mutex> lock(mutex_);
+    ssrcs_.erase(ssrc);
+  }
+
+  bool Contains(uint32_t ssrc) {
+    std::lock_guard<std::mutex> lock(mutex_);
+    return ssrcs_.count(ssrc) > 0;
+  }
+
+ private:
+  SSRCManager() = default;
+  ~SSRCManager() = default;
+  SSRCManager(const SSRCManager&) = delete;
+  SSRCManager& operator=(const SSRCManager&) = delete;
+
+  std::unordered_set<uint32_t> ssrcs_;
+  std::mutex mutex_;
+};
+
 #endif