From 9b1fc23d2460169818e12a128cce244c7f70391d Mon Sep 17 00:00:00 2001
From: victor <victor@e16421f0-f15b-0410-abcd-98678b794739>
Date: Sat, 14 Nov 2009 17:27:21 +0000
Subject: [PATCH] ping-pong is back

git-svn-id: https://ttuki.vtt.fi/svn/p2p-next/TUD/p2tp/trunk@554 e16421f0-f15b-0410-abcd-98678b794739
---
 ext/send_control.cpp | 24 +++++++++++++++++++++---
 ext/send_control.h   | 17 ++++++++++++++++-
 p2tp.cpp             |  2 +-
 3 files changed, 38 insertions(+), 5 deletions(-)

diff --git a/ext/send_control.cpp b/ext/send_control.cpp
index 256bab9..c622f67 100644
--- a/ext/send_control.cpp
+++ b/ext/send_control.cpp
@@ -24,6 +24,27 @@ void    SendController::Schedule (tint next_time) {
     ch_->Schedule(next_time);
 }
 
+bool    PingPongController::MaySendData() {
+    return ch_->data_out_.empty();
+}
+
+void    PingPongController::OnDataSent(bin64_t b) {
+    Schedule(NOW+ch_->rtt_avg_+std::max(ch_->dev_avg_*4,500*TINT_MSEC));
+    if (++sent_>=10)
+        Swap(new KeepAliveController(this));
+    else if (++unanswered_>=3)
+        Schedule(TINT_NEVER);
+}
+
+void    PingPongController::OnDataRecvd(bin64_t b) {
+    unanswered_ = 0;
+    Schedule(NOW); // pong
+}
+
+void    PingPongController::OnAckRcvd(bin64_t ackd) {
+    if (ackd!=bin64_t::NONE)
+        Swap(new SlowStartController(this));
+}
 
 
 KeepAliveController::KeepAliveController (Channel* ch) : SendController(ch), delay_(ch->rtt_avg_) {
@@ -60,9 +81,6 @@ void    KeepAliveController::OnDataRecvd(bin64_t b) {
     if (b!=bin64_t::NONE && b!=bin64_t::ALL) { // channel is alive
         delay_ = ch_->rtt_avg_;
         Schedule(NOW); // schedule an ACK; TODO: aggregate
-    } else  {
-        delay_ = ch_->rtt_avg_;
-        Schedule(NOW);
     }
 }
     
diff --git a/ext/send_control.h b/ext/send_control.h
index 91318a6..e4887e0 100644
--- a/ext/send_control.h
+++ b/ext/send_control.h
@@ -44,7 +44,22 @@ struct SendController {
     virtual         ~SendController() {}
 };
 
-
+struct PingPongController : public SendController {
+    
+    int     sent_, unanswered_;
+    
+    PingPongController (SendController* orig) :
+        SendController(orig), sent_(0), unanswered_(0) {} 
+    PingPongController (Channel* ch) : 
+        unanswered_(0), sent_(0), SendController(ch) {}
+    const char* type() const { return "PingPong"; }
+    bool    MaySendData();
+    void    OnDataSent(bin64_t b);
+    void    OnDataRecvd(bin64_t b);
+    void    OnAckRcvd(bin64_t ackd) ;
+    ~PingPongController() {}
+    
+};
 /** Mission of the keepalive controller to keep the channel
     alive as no data sending happens; If no data is transmitted
     in either direction, inter-packet times grow exponentially
diff --git a/p2tp.cpp b/p2tp.cpp
index 7fe32df..2db3de2 100644
--- a/p2tp.cpp
+++ b/p2tp.cpp
@@ -48,7 +48,7 @@ Channel::Channel	(FileTransfer* transfer, int socket, Address peer_addr) :
         peer_ = tracker;
 	this->id = channels.size();
 	channels.push_back(this);
-    cc_ = new KeepAliveController(this);
+    cc_ = new PingPongController(this);
     Schedule(NOW); // FIXME ugly
 }
 
-- 
2.20.1