Added handling of session ID <sess-id> and session version <sess-version> in the Origin ("o=") field of the Sources SDP files.

Session ID is the Node ID plus the source ID.
Session version is the session ID plus an increasing version identifier.
This fixes issue #10 and allows Dante Controller to properly handle the daemon Sources.

daemon/session_manager.cpp

@@ -37,7 +37,6 @@
 #include "utils.hpp"
 #include "session_manager.hpp"
 
-
 static uint8_t get_codec_word_lenght(const std::string& codec) {
   if (codec == "L16") {
     return 2;
@@ -492,6 +491,10 @@ std::error_code SessionManager::add_source(const StreamSource& source) {
   info.refclk_ptp_traceable = source.refclk_ptp_traceable;
   info.enabled = source.enabled;
   info.io = source.io;
+
+  auto ip_addr = htonl(config_->get_ip_addr());
+  info.session_id = (ip_addr << 16) + (ip_addr >> 16) + source.id;
+  info.session_version = info.session_id + g_session_version++;
   // info.m_ui32PlayOutDelay = 0; // only for Sink
 
   std::unique_lock sources_lock(sources_mutex_);
@@ -531,10 +534,14 @@ std::error_code SessionManager::add_source(const StreamSource& source) {
   return ret;
 }
 
-std::string SessionManager::get_removed_source_sdp_(uint32_t id,
+std::string SessionManager::get_removed_source_sdp_(
-                                                    uint32_t addr) const {
+    uint32_t id,
-  std::string sdp("o=- " + std::to_string(id) + " 0 IN IP4 " +
+    uint32_t src_addr,
-                  ip::address_v4(addr).to_string() + "\n");
+    uint32_t session_id,
+    uint32_t session_version) const {
+  std::string sdp("o=- " + std::to_string(session_id) + " " +
+                  std::to_string(session_version) + " IN IP4 " +
+                  ip::address_v4(src_addr).to_string() + "\n");
   return sdp;
 }
 
@@ -556,7 +563,7 @@ std::string SessionManager::get_source_sdp_(uint32_t id,
   // build SDP
   std::stringstream ss;
   ss << "v=0\n"
-     << "o=- " << static_cast<unsigned>(id) << " 0 IN IP4 "
+     << "o=- " << info.session_id << " " << info.session_version << " IN IP4 "
      << ip::address_v4(info.stream.m_ui32SrcIP).to_string() << "\n"
      << "s=" << get_node_id(config_->get_ip_addr()) << " "
      << info.stream.m_cName << "\n"
@@ -874,14 +881,15 @@ size_t SessionManager::process_sap() {
   for (auto const& [id, info] : sources_) {
     if (info.enabled) {
       // retrieve current active source SDP
-      std::string sdp = get_source_sdp_(id, info);
+      auto sdp = get_source_sdp_(id, info);
       // compute source 16bit crc
       uint16_t msg_crc =
           crc16(reinterpret_cast<const uint8_t*>(sdp.c_str()), sdp.length());
       // compute source hash
       uint32_t msg_id_hash = (static_cast<uint32_t>(id) << 16) + msg_crc;
       // add/update this source in the announced sources
-      announced_sources_[msg_id_hash] = info.stream.m_ui32RTCPSrcIP;
+      announced_sources_[msg_id_hash] = {info.stream.m_ui32RTCPSrcIP,
+                                         info.session_id, info.session_version};
       // add this source to the currently active sources
       active_sources.insert(msg_id_hash);
       // remove this source from deleted sources (if present)
@@ -894,11 +902,15 @@ size_t SessionManager::process_sap() {
   }
 
   // check for sources that are no longer announced and send deletion/s
-  for (auto const& [msg_id_hash, src_addr] : announced_sources_) {
+  for (auto const& [msg_id_hash, info] : announced_sources_) {
+    auto src_addr = std::get<0>(info);
+    auto session_id = std::get<1>(info);
+    auto session_version = std::get<2>(info);
     // check if this source is no longer announced
     if (active_sources.find(msg_id_hash) == active_sources.end()) {
       // retrieve deleted source SDP
-      std::string sdp = get_removed_source_sdp_(msg_id_hash >> 16, src_addr);
+      std::string sdp = get_removed_source_sdp_(msg_id_hash >> 16, src_addr,
+                                                session_id, session_version);
       // send deletion for this source
       sap_.deletion(static_cast<uint16_t>(msg_id_hash), src_addr, sdp);
       // update amount of byte sent
@@ -926,15 +938,18 @@ size_t SessionManager::process_sap() {
 
 void SessionManager::on_update_sources() {
   // trigger sources SDP file update
-  std::shared_lock sources_lock(sources_mutex_);
+  sources_mutex_.lock();
-  for (auto const& [id, info] : sources_) {
+  for (auto& [id, info] : sources_) {
     for (auto cb : update_source_observers) {
+      info.session_version++;
       cb(id, info.stream.m_cName, get_source_sdp_(id, info));
     }
   }
+  sources_mutex_.unlock();
+  g_session_version++;
 }
 
-void SessionManager::on_ptp_status_locked() {
+void SessionManager::on_ptp_status_locked() const {
   // set sample rate, this may require seconds
   (void)driver_->set_sample_rate(driver_->get_current_sample_rate());
 }
@@ -1049,9 +1064,13 @@ bool SessionManager::worker() {
   }
 
   // at end, send deletion for all announced sources
-  for (auto const& [msg_id_hash, src_addr] : announced_sources_) {
+  for (auto const& [msg_id_hash, info] : announced_sources_) {
+    auto src_addr = std::get<0>(info);
+    auto session_id = std::get<1>(info);
+    auto session_version = std::get<2>(info);
     // retrieve deleted source SDP
-    std::string sdp = get_removed_source_sdp_(msg_id_hash >> 16, src_addr);
+    std::string sdp = get_removed_source_sdp_(msg_id_hash >> 16, src_addr,
+                                              session_id, session_version);
     // send deletion for this source
     sap_.deletion(static_cast<uint16_t>(msg_id_hash), src_addr, sdp);
   }

daemon/session_manager.hpp

@@ -90,6 +90,8 @@ struct StreamInfo {
   bool sink_use_sdp{true};
   std::string sink_source;
   std::string sink_sdp;
+  uint32_t session_id{0};
+  uint32_t session_version{0};
 };
 
 class SessionManager {
@@ -166,11 +168,14 @@ class SessionManager {
   void on_add_sink(const StreamSink& sink, const StreamInfo& info);
   void on_remove_sink(const StreamInfo& info);
 
-  void on_ptp_status_locked();
+  void on_ptp_status_locked() const;
 
   void on_update_sources();
 
-  std::string get_removed_source_sdp_(uint32_t id, uint32_t src_addr) const;
+  std::string get_removed_source_sdp_(uint32_t id,
+                                      uint32_t src_addr,
+                                      uint32_t session_id,
+                                      uint32_t session_version) const;
   std::string get_source_sdp_(uint32_t id, const StreamInfo& info) const;
   StreamSource get_source_(uint8_t id, const StreamInfo& info) const;
   StreamSink get_sink_(uint8_t id, const StreamInfo& info) const;
@@ -201,7 +206,10 @@ class SessionManager {
   mutable std::shared_mutex sinks_mutex_;
 
   /* current announced sources */
-  std::map<uint32_t /* msg_id_hash */, uint32_t /* src_addr */>
+  std::map<uint32_t /* msg_id_hash */,
+           std::tuple<uint32_t /* src_addr */,
+                      uint32_t /* session_id */,
+                      uint32_t /* session_version */> >
       announced_sources_;
 
   /* number of deletions sent for a  a deleted source */
@@ -218,6 +226,9 @@ class SessionManager {
 
   SAP sap_{config_->get_sap_mcast_addr()};
   IGMP igmp_;
+
+  /* used to handle session versioning */
+  inline static std::atomic<uint16_t> g_session_version{0};
 };
 
 #endif