Rip out resolver and use anycast address instead. In the long term existing TCP proxy dies anyway. Fixes static build problem for old Linux versions.

objects.mk

@@ -26,7 +26,6 @@ OBJS=\
 	node/Tag.o \
 	node/Topology.o \
 	node/Utils.o \
-	osdep/BackgroundResolver.o \
 	osdep/ManagedRoute.o \
 	osdep/Http.o \
 	osdep/OSUtils.o \

osdep/BackgroundResolver.cpp

@@ -1,121 +0,0 @@
-/*
- * ZeroTier One - Network Virtualization Everywhere
- * Copyright (C) 2011-2016  ZeroTier, Inc.  https://www.zerotier.com/
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-
-#include "OSUtils.hpp"
-#include "Thread.hpp"
-#include "BackgroundResolver.hpp"
-
-namespace ZeroTier {
-
-/*
- * We can't actually abort a job. This is a legacy characteristic of the
- * ancient synchronous resolver APIs. So to abort jobs, we just abandon
- * them by setting their parent to null.
- */
-class BackgroundResolverJob
-{
-public:
-	std::string name;
-	BackgroundResolver *volatile parent;
-	Mutex lock;
-
-	void threadMain()
-		throw()
-	{
-		std::vector<InetAddress> ips;
-		try {
-			ips = OSUtils::resolve(name.c_str());
-		} catch ( ... ) {}
-		{
-			Mutex::Lock _l(lock);
-			BackgroundResolver *p = parent;
-			if (p)
-				p->_postResult(ips);
-		}
-		delete this;
-	}
-};
-
-BackgroundResolver::BackgroundResolver(const char *name) :
-	_name(name),
-	_job((BackgroundResolverJob *)0),
-	_callback(0),
-	_arg((void *)0),
-	_ips(),
-	_lock()
-{
-}
-
-BackgroundResolver::~BackgroundResolver()
-{
-	abort();
-}
-
-std::vector<InetAddress> BackgroundResolver::get() const
-{
-	Mutex::Lock _l(_lock);
-	return _ips;
-}
-
-void BackgroundResolver::resolveNow(void (*callback)(BackgroundResolver *,void *),void *arg)
-{
-	Mutex::Lock _l(_lock);
-
-	if (_job) {
-		Mutex::Lock _l2(_job->lock);
-		_job->parent = (BackgroundResolver *)0;
-		_job = (BackgroundResolverJob *)0;
-	}
-
-	BackgroundResolverJob *j = new BackgroundResolverJob();
-	j->name = _name;
-	j->parent = this;
-
-	_job = j;
-	_callback = callback;
-	_arg = arg;
-
-	_jobThread = Thread::start(j);
-}
-
-void BackgroundResolver::abort()
-{
-	Mutex::Lock _l(_lock);
-	if (_job) {
-		Mutex::Lock _l2(_job->lock);
-		_job->parent = (BackgroundResolver *)0;
-		_job = (BackgroundResolverJob *)0;
-	}
-}
-
-void BackgroundResolver::_postResult(const std::vector<InetAddress> &ips)
-{
-	void (*cb)(BackgroundResolver *,void *);
-	void *a;
-	{
-		Mutex::Lock _l(_lock);
-		_job = (BackgroundResolverJob *)0;
-		cb = _callback;
-		a = _arg;
-		_ips = ips;
-	}
-	if (cb)
-		cb(this,a);
-}
-
-} // namespace ZeroTier

osdep/BackgroundResolver.hpp

@@ -1,118 +0,0 @@
-/*
- * ZeroTier One - Network Virtualization Everywhere
- * Copyright (C) 2011-2016  ZeroTier, Inc.  https://www.zerotier.com/
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-
-#ifndef ZT_BACKGROUNDRESOLVER_HPP
-#define ZT_BACKGROUNDRESOLVER_HPP
-
-#include <vector>
-#include <string>
-
-#include "../node/Constants.hpp"
-#include "../node/Mutex.hpp"
-#include "../node/InetAddress.hpp"
-#include "../node/NonCopyable.hpp"
-#include "Thread.hpp"
-
-namespace ZeroTier {
-
-class BackgroundResolverJob;
-
-/**
- * A simple background resolver
- */
-class BackgroundResolver : NonCopyable
-{
-	friend class BackgroundResolverJob;
-
-public:
-	/**
-	 * Construct a new resolver
-	 *
-	 * resolveNow() must be called to actually initiate background resolution.
-	 *
-	 * @param name Name to resolve
-	 */
-	BackgroundResolver(const char *name);
-
-	~BackgroundResolver();
-
-	/**
-	 * @return Most recent resolver results or empty vector if none
-	 */
-	std::vector<InetAddress> get() const;
-
-	/**
-	 * Launch a background resolve job now
-	 *
-	 * If a resolve job is currently in progress, it is aborted and another
-	 * job is started.
-	 *
-	 * Note that jobs can't actually be aborted due to the limitations of the
-	 * ancient synchronous OS resolver APIs. As a result, in progress jobs
-	 * that are aborted are simply abandoned. Don't call this too frequently
-	 * or background threads might pile up.
-	 *
-	 * @param callback Callback function to receive notification or NULL if none
-	 * @praam arg Second argument to callback function
-	 */
-	void resolveNow(void (*callback)(BackgroundResolver *,void *) = 0,void *arg = 0);
-
-	/**
-	 * Abort (abandon) any current resolve jobs
-	 */
-	void abort();
-
-	/**
-	 * @return True if a background job is in progress
-	 */
-	inline bool running() const
-	{
-		Mutex::Lock _l(_lock);
-		return (_job != (BackgroundResolverJob *)0);
-	}
-
-	/**
-	 * Wait for pending job to complete (if any)
-	 */
-	inline void wait() const
-	{
-		Thread t;
-		{
-			Mutex::Lock _l(_lock);
-			if (!_job)
-				return;
-			t = _jobThread;
-		}
-		Thread::join(t);
-	}
-
-private:
-	void _postResult(const std::vector<InetAddress> &ips);
-
-	std::string _name;
-	BackgroundResolverJob *_job;
-	Thread _jobThread;
-	void (*_callback)(BackgroundResolver *,void *);
-	void *_arg;
-	std::vector<InetAddress> _ips;
-	Mutex _lock;
-};
-
-} // namespace ZeroTier
-
-#endif

osdep/OSUtils.cpp

@@ -256,34 +256,6 @@ int64_t OSUtils::getFileSize(const char *path)
 	return -1;
 }
 
-std::vector<InetAddress> OSUtils::resolve(const char *name)
-{
-	std::vector<InetAddress> r;
-	std::vector<InetAddress>::iterator i;
-	InetAddress tmp;
-	struct addrinfo *ai = (struct addrinfo *)0,*p;
-	if (!getaddrinfo(name,(const char *)0,(const struct addrinfo *)0,&ai)) {
-		try {
-			p = ai;
-			while (p) {
-				if ((p->ai_addr)&&((p->ai_addr->sa_family == AF_INET)||(p->ai_addr->sa_family == AF_INET6))) {
-					tmp = *(p->ai_addr);
-					for(i=r.begin();i!=r.end();++i) {
-						if (i->ipsEqual(tmp))
-							goto skip_add_inetaddr;
-					}
-					r.push_back(tmp);
-				}
-skip_add_inetaddr:
-				p = p->ai_next;
-			}
-		} catch ( ... ) {}
-		freeaddrinfo(ai);
-	}
-	std::sort(r.begin(),r.end());
-	return r;
-}
-
 bool OSUtils::readFile(const char *path,std::string &buf)
 {
 	char tmp[1024];

service/OneService.cpp

@@ -43,7 +43,6 @@
 #include "../osdep/Thread.hpp"
 #include "../osdep/OSUtils.hpp"
 #include "../osdep/Http.hpp"
-#include "../osdep/BackgroundResolver.hpp"
 #include "../osdep/PortMapper.hpp"
 #include "../osdep/Binder.hpp"
 #include "../osdep/ManagedRoute.hpp"
@@ -136,9 +135,8 @@ namespace ZeroTier { typedef BSDEthernetTap EthernetTap; }
 // Path under ZT1 home for controller database if controller is enabled
 #define ZT_CONTROLLER_DB_PATH "controller.d"
 
-// TCP fallback relay host -- geo-distributed using Amazon Route53 geo-aware DNS
+// TCP fallback relay (run by ZeroTier, Inc. -- this will eventually go away)
-#define ZT_TCP_FALLBACK_RELAY "tcp-fallback.zerotier.com"
+#define ZT_TCP_FALLBACK_RELAY "204.80.128.1/443"
-#define ZT_TCP_FALLBACK_RELAY_PORT 443
 
 // Frequency at which we re-resolve the TCP fallback relay
 #define ZT_TCP_FALLBACK_RERESOLVE_DELAY 86400000
@@ -263,7 +261,6 @@ public:
 	// begin member variables --------------------------------------------------
 
 	const std::string _homePath;
-	BackgroundResolver _tcpFallbackResolver;
 	EmbeddedNetworkController *_controller;
 	Phy<OneServiceImpl *> _phy;
 	Node *_node;
@@ -368,7 +365,6 @@ public:
 
 	OneServiceImpl(const char *hp,unsigned int port) :
 		_homePath((hp) ? hp : ".")
-		,_tcpFallbackResolver(ZT_TCP_FALLBACK_RELAY)
 		,_controller((EmbeddedNetworkController *)0)
 		,_phy(this,false,true)
 		,_node((Node *)0)
@@ -710,7 +706,6 @@ public:
 			uint64_t clockShouldBe = OSUtils::now();
 			_lastRestart = clockShouldBe;
 			uint64_t lastTapMulticastGroupCheck = 0;
-			uint64_t lastTcpFallbackResolve = 0;
 			uint64_t lastBindRefresh = 0;
 			uint64_t lastUpdateCheck = clockShouldBe;
 			uint64_t lastLocalInterfaceAddressCheck = (clockShouldBe - ZT_LOCAL_INTERFACE_CHECK_INTERVAL) + 15000; // do this in 15s to give portmapper time to configure and other things time to settle
@@ -765,11 +760,6 @@ public:
 					dl = _nextBackgroundTaskDeadline;
 				}
 
-				if ((now - lastTcpFallbackResolve) >= ZT_TCP_FALLBACK_RERESOLVE_DELAY) {
-					lastTcpFallbackResolve = now;
-					_tcpFallbackResolver.resolveNow();
-				}
-
 				if ((_tcpFallbackTunnel)&&((now - _lastDirectReceiveFromGlobal) < (ZT_TCP_FALLBACK_AFTER / 2)))
 					_phy.close(_tcpFallbackTunnel->sock);
 
@@ -1617,16 +1607,9 @@ public:
 						_tcpFallbackTunnel->writeBuf.append(reinterpret_cast<const char *>(reinterpret_cast<const void *>(&(reinterpret_cast<const struct sockaddr_in *>(addr)->sin_port))),2);
 						_tcpFallbackTunnel->writeBuf.append((const char *)data,len);
 					} else if (((now - _lastSendToGlobalV4) < ZT_TCP_FALLBACK_AFTER)&&((now - _lastSendToGlobalV4) > (ZT_PING_CHECK_INVERVAL / 2))) {
-						std::vector<InetAddress> tunnelIps(_tcpFallbackResolver.get());
+						bool connected = false;
-						if (tunnelIps.empty()) {
+						const InetAddress addr(ZT_TCP_FALLBACK_RELAY);
-							if (!_tcpFallbackResolver.running())
+						_phy.tcpConnect(reinterpret_cast<const struct sockaddr *>(&addr),connected);
-								_tcpFallbackResolver.resolveNow();
-						} else {
-							bool connected = false;
-							InetAddress addr(tunnelIps[(unsigned long)now % tunnelIps.size()]);
-							addr.setPort(ZT_TCP_FALLBACK_RELAY_PORT);
-							_phy.tcpConnect(reinterpret_cast<const struct sockaddr *>(&addr),connected);
-						}
 					}
 				}
 				_lastSendToGlobalV4 = now;