From 95a23dc7ec9a2ce55cab337b78b662a30ec2b986 Mon Sep 17 00:00:00 2001
From: Adam Ierymenko <adam.ierymenko@gmail.com>
Date: Fri, 9 Aug 2013 17:20:40 -0400
Subject: Fix for another wonderful C++ threading race condition.

---
 node/EthernetTap.cpp | 4 ++++
 node/Network.cpp     | 4 ++++
 node/Network.hpp     | 1 +
 3 files changed, 9 insertions(+)

(limited to 'node')

diff --git a/node/EthernetTap.cpp b/node/EthernetTap.cpp
index 4c300d0b..e6536223 100644
--- a/node/EthernetTap.cpp
+++ b/node/EthernetTap.cpp
@@ -557,6 +557,10 @@ void EthernetTap::threadMain()
 	char getBuf[4096 + 14];
 	Buffer<4096> data;
 
+	// Wait for a moment after startup -- wait for Network to finish
+	// constructing itself.
+	Thread::sleep(500);
+
 	FD_ZERO(&readfds);
 	FD_ZERO(&nullfds);
 	int nfds = (int)std::max(_shutdownSignalPipe[0],_fd) + 1;
diff --git a/node/Network.cpp b/node/Network.cpp
index 9227cd34..3593b732 100644
--- a/node/Network.cpp
+++ b/node/Network.cpp
@@ -139,6 +139,7 @@ SharedPtr<Network> Network::newInstance(const RuntimeEnvironment *renv,uint64_t
 	// that then causes the Network instance to be deleted before it is finished
 	// being constructed. C++ edge cases, how I love thee.
 	SharedPtr<Network> nw(new Network());
+	nw->_ready = false; // disable handling of Ethernet frames during construct
 	nw->_r = renv;
 	nw->_rlLimit.bytesPerSecond = ZT_MULTICAST_DEFAULT_BYTES_PER_SECOND;
 	nw->_rlLimit.maxBalance = ZT_MULTICAST_DEFAULT_RATE_MAX_BALANCE;
@@ -150,6 +151,7 @@ SharedPtr<Network> Network::newInstance(const RuntimeEnvironment *renv,uint64_t
 	if (nw->controller() == renv->identity.address()) // sanity check, this isn't supported for now
 		throw std::runtime_error("cannot add a network for which I am the netconf master");
 	nw->_restoreState();
+	nw->_ready = true; // enable handling of Ethernet frames
 	nw->requestConfiguration();
 	return nw;
 }
@@ -267,6 +269,8 @@ Network::Status Network::status() const
 
 void Network::_CBhandleTapData(void *arg,const MAC &from,const MAC &to,unsigned int etherType,const Buffer<4096> &data)
 {
+	if (!((Network *)arg)->_ready)
+		return;
 	const RuntimeEnvironment *_r = ((Network *)arg)->_r;
 	try {
 		_r->sw->onLocalEthernet(SharedPtr<Network>((Network *)arg),from,to,etherType,data);
diff --git a/node/Network.hpp b/node/Network.hpp
index 312912db..e80d2e65 100644
--- a/node/Network.hpp
+++ b/node/Network.hpp
@@ -472,6 +472,7 @@ private:
 	uint64_t _id;
 	volatile uint64_t _lastConfigUpdate;
 	volatile bool _destroyOnDelete;
+	volatile bool _ready;
 
 	Mutex _lock;
 
-- 
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