Create RTCP for every connection

RTCP is used for SSRC collision checking.
The actual RTCP functionality must be enabled explictly by
calling create_rtcp().

The line between packet validation and RTCP is becoming a little
blurry and a more coherent model for validation is a future task:

src/conn.cc

@@ -3,6 +3,7 @@
 #include <unistd.h>
 #endif
 
+#include <cassert>
 #include <cstring>
 #include <iostream>
 
@@ -188,10 +189,7 @@ void kvz_rtp::connection::update_rtp_sequence(uint8_t *buffer)
 
 rtp_error_t kvz_rtp::connection::create_rtcp(std::string dst_addr, int dst_port, int src_port)
 {
-    if ((rtcp_ = new kvz_rtp::rtcp(rtp_ssrc_, reader_)) == nullptr) {
-        LOG_ERROR("Failed to allocate RTCP instance!");
-        return RTP_MEMORY_ERROR;
-    }
+    assert(rtcp_ != nullptr);
 
     if ((rtp_errno = rtcp_->add_participant(dst_addr, dst_port, src_port, clock_rate_)) != RTP_OK) {
         LOG_ERROR("Failed to add RTCP participant!");

src/reader.cc

@@ -77,6 +77,11 @@ rtp_error_t kvz_rtp::reader::start()
     }
     runner_->detach();
 
+    if ((rtcp_ = new kvz_rtp::rtcp(get_ssrc(), true)) == nullptr) {
+        LOG_ERROR("Failed to allocate RTCP instance!");
+        return RTP_MEMORY_ERROR;
+    }
+
     return RTP_OK;
 }
 

src/rtcp.cc

@@ -23,7 +23,7 @@ kvz_rtp::rtcp::rtcp(uint32_t ssrc, bool receiver):
     tp_(0), tc_(0), tn_(0), pmembers_(0),
     members_(0), senders_(0), rtcp_bandwidth_(0),
     we_sent_(0), avg_rtcp_pkt_pize_(0), rtcp_pkt_count_(0),
-    initial_(true), active_(false), num_receivers_(0)
+    initial_(true), active_(false), num_receivers_(0), runner_(nullptr)
 {
     ssrc_  = ssrc;
 
@@ -127,6 +127,9 @@ rtp_error_t kvz_rtp::rtcp::start()
 
 rtp_error_t kvz_rtp::rtcp::terminate()
 {
+    if (runner_ == nullptr)
+        return RTP_OK;
+
     /* when the member count is less than 50,
      * we can just send the BYE message and destroy the session */
     if (members_ < 50) {
@@ -377,6 +380,18 @@ rtp_error_t kvz_rtp::rtcp::receiver_update_stats(kvz_rtp::frame::rtp_frame *fram
         return RTP_INVALID_VALUE;
     }
 
+    /* RTCP runner is not running so we don't need to do any other checks,
+     * just create new participant so we can check for SSRC collisions */
+    if (runner_ == nullptr) {
+        if (participants_.find(frame->header.ssrc) == participants_.end()) {
+            auto participant = new struct participant;
+            participant->address = frame->src_addr;
+            participants_[frame->header.ssrc] = participant;
+        }
+
+        return RTP_OK;
+    }
+
     if (!kvz_rtp::rtcp::is_participant(frame->header.ssrc)) {
         LOG_WARN("Got RTP packet from unknown source: 0x%x", frame->header.ssrc);
         init_new_participant(frame);

src/writer.cc

@@ -63,6 +63,11 @@ rtp_error_t kvz_rtp::writer::start()
     addr_out_ = socket_.create_sockaddr(AF_INET, dst_addr_, dst_port_);
     socket_.set_sockaddr(addr_out_);
 
+    if ((rtcp_ = new kvz_rtp::rtcp(get_ssrc(), false)) == nullptr) {
+        LOG_ERROR("Failed to allocate RTCP instance!");
+        return RTP_MEMORY_ERROR;
+    }
+
     return RTP_OK;
 }