add network event script support

Based on PR #1669 of @joseph-henry

Co-authored-by: Joseph Henry
Signed-off-by: Oskari Rauta <oskari.rauta@gmail.com>

one.cpp

@@ -1996,6 +1996,7 @@ static void printHelp(const char *cn,FILE *out)
 
 #ifdef __UNIX_LIKE__
 	fprintf(out,"  -d                - Fork and run as daemon (Unix-ish OSes)" ZT_EOL_S);
+	fprintf(out,"  -s<path>          - path to script to execute on network events" ZT_EOL_S);
 #endif // __UNIX_LIKE__
 
 #ifdef __WINDOWS__
@@ -2012,13 +2013,13 @@ static void printHelp(const char *cn,FILE *out)
 class _OneServiceRunner
 {
 public:
-	_OneServiceRunner(const char *pn,const std::string &hd,unsigned int p) : progname(pn),returnValue(0),port(p),homeDir(hd) {}
+	_OneServiceRunner(const char *pn,const std::string &hd,unsigned int p, std::string &sp) : progname(pn),returnValue(0),port(p),homeDir(hd),scriptPath(sp) {}
 	void threadMain()
 		throw()
 	{
 		try {
 			for(;;) {
-				zt1Service = OneService::newInstance(homeDir.c_str(),port);
+				zt1Service = OneService::newInstance(homeDir.c_str(),port,scriptPath.c_str());
 				switch(zt1Service->run()) {
 					case OneService::ONE_STILL_RUNNING: // shouldn't happen, run() won't return until done
 					case OneService::ONE_NORMAL_TERMINATION:
@@ -2053,6 +2054,7 @@ public:
 	unsigned int returnValue;
 	unsigned int port;
 	const std::string &homeDir;
+	const std::string &scriptPath;
 };
 
 #ifdef __WINDOWS__
@@ -2082,6 +2084,7 @@ int main(int argc,char **argv)
 	signal(SIGTERM,&_sighandlerQuit);
 	signal(SIGQUIT,&_sighandlerQuit);
 	signal(SIGINT,&_sighandlerQuit);
+	signal(SIGCHLD, SIG_IGN);
 
 	/* Ensure that there are no inherited file descriptors open from a previous
 	 * incarnation. This is a hack to ensure that GitHub issue #61 or variants
@@ -2115,7 +2118,7 @@ int main(int argc,char **argv)
 	if ((strstr(argv[0],"zerotier-cli"))||(strstr(argv[0],"ZEROTIER-CLI")))
 		return cli(argc,argv);
 
-	std::string homeDir;
+	std::string homeDir, scriptPath;
 	unsigned int port = ZT_DEFAULT_PORT;
 	bool skipRootCheck = false;
 
@@ -2135,6 +2138,11 @@ int main(int argc,char **argv)
 				case 'd': // Run in background as daemon
 					runAsDaemon = true;
 					break;
+				case 's': // script to run on network events
+					if (argv[i][2]) {
+						scriptPath = argv[i] + 2;
+					} else printHelp(argv[0],stdout);
+					break;
 #endif // __UNIX_LIKE__
 
 				case 'U':
@@ -2306,7 +2314,7 @@ int main(int argc,char **argv)
 	}
 #endif // __UNIX_LIKE__
 
-	_OneServiceRunner thr(argv[0],homeDir,port);
+	_OneServiceRunner thr(argv[0],homeDir,port,scriptPath);
 	thr.threadMain();
 	//Thread::join(Thread::start(&thr));
 

osdep/OSUtils.cpp

@@ -11,34 +11,34 @@
  */
 /****/
 
-#include <stdio.h>
-#include <string.h>
-#include <stdlib.h>
-#include <stdarg.h>
-#include <sys/stat.h>
-#include <stdlib.h>
-
 #include "../node/Constants.hpp"
 #include "../node/Utils.hpp"
 
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+
 #ifdef __UNIX_LIKE__
-#include <unistd.h>
+#include <dirent.h>
 #include <errno.h>
 #include <fcntl.h>
-#include <sys/types.h>
+#include <netdb.h>
 #include <sys/socket.h>
 #include <sys/stat.h>
+#include <sys/types.h>
 #include <sys/uio.h>
-#include <dirent.h>
+#include <sys/wait.h>
-#include <netdb.h>
+#include <unistd.h>
 #endif
 
 #ifdef __WINDOWS__
-#include <windows.h>
-#include <wincrypt.h>
-#include <shlobj.h>
-#include <netioapi.h>
 #include <iphlpapi.h>
+#include <netioapi.h>
+#include <shlobj.h>
+#include <wincrypt.h>
+#include <windows.h>
 #endif
 
 #include "OSUtils.hpp"
@@ -551,6 +551,53 @@ std::string OSUtils::jsonBinFromHex(const nlohmann::json &jv)
 	return std::string();
 }
 
+void OSUtils::_hookCmd(const char* scriptPath, const uint64_t nwid, const char *homePath, ZT_VirtualNetworkConfigOperation op)
+{
+	if (! scriptPath || ! strlen(scriptPath) || nwid == 0) {
+#ifdef ZT_TRACE
+		fprintf(stderr, "no script path specified\n");
+#endif
+		return;
+	}
+	long p = (long)fork();
+
+	if (p > 0) {
+#ifdef ZT_TRACE
+		fprintf(stderr, "Running network event hook script (%s)\n", scriptPath);
+#endif
+		//int exitcode = -1;
+		//::waitpid(p, &exitcode, 0);
+	}
+	else if (p == 0) {
+		::close(STDOUT_FILENO);
+		::close(STDERR_FILENO);
+		char cmdBuf[128] = { 0 };
+		OSUtils::ztsnprintf(cmdBuf, sizeof(cmdBuf), "%s", scriptPath);
+		char nwidStr[17] = { 0 };
+		OSUtils::ztsnprintf(nwidStr, sizeof(nwidStr), "%.16llx", nwid);
+		std::string cmd;
+		switch (op) {
+			case ZT_VIRTUAL_NETWORK_CONFIG_OPERATION_UP:
+				cmd = std::string(cmdBuf) + " network_up " + std::string(nwidStr) + " " + std::string(homePath) + "";
+				//::execl("/bin/sh", "sh", cmdBuf, "network_up", nwidStr, homePath, "&", (const char*)0);
+				break;
+			case ZT_VIRTUAL_NETWORK_CONFIG_OPERATION_CONFIG_UPDATE:
+				cmd = std::string(cmdBuf) + " network_update " + std::string(nwidStr) + " " + std::string(homePath) + "";
+				//::execl("/bin/sh", "sh", cmdBuf, "network_update", nwidStr, homePath, "&", (const char*)0);
+				break;
+			case ZT_VIRTUAL_NETWORK_CONFIG_OPERATION_DOWN:	 // Same as _DESTROY
+				cmd = std::string(cmdBuf) + " network_down " + std::string(nwidStr) + " " + std::string(homePath) + "";
+				//::execl("/bin/sh", "sh", cmdBuf, "network_down", nwidStr, homePath, "&", (const char*)0);
+				break;
+			default:
+				break;
+		}
+		// Using system instead of execl, because execl blocks connections through cli
+		if (!cmd.empty()) ::system(cmd.c_str());
+		::_exit(-1);
+	}
+}
+
 #endif // OMIT_JSON_SUPPORT
 
 // Used to convert HTTP header names to ASCII lower case

osdep/OSUtils.hpp

@@ -269,6 +269,16 @@ public:
 	 */
 	static std::string platformDefaultHomePath();
 
+	/**
+	 * Executes a system script specified by user
+	 *
+	 * @param scriptPath The full path to the script that should be run on each network event
+	 * @param nwid The Network ID of the network in question
+	 * @param homePath full patch to homepath containing connections settings and data
+	 * @param op The operation performed up on the network
+	 */
+	static void _hookCmd(const char *scriptPath, const uint64_t nwid, const char *homePath, ZT_VirtualNetworkConfigOperation op);
+
 #ifndef OMIT_JSON_SUPPORT
 	static nlohmann::json jsonParse(const std::string &buf);
 	static std::string jsonDump(const nlohmann::json &j,int indentation = 1);

service/OneService.cpp

@@ -704,8 +704,11 @@ public:
 	// begin member variables --------------------------------------------------
 
 	const std::string _homePath;
+
 	std::string _authToken;
 	std::string _controllerDbPath;
+	std::string _eventHookScriptPath;
+
 	const std::string _networksPath;
 	const std::string _moonsPath;
 
@@ -804,9 +807,10 @@ public:
 
 	// end member variables ----------------------------------------------------
 
-	OneServiceImpl(const char *hp,unsigned int port) :
+	OneServiceImpl(const char *hp,unsigned int port,const char *sp) :
 		_homePath((hp) ? hp : ".")
 		,_controllerDbPath(_homePath + ZT_PATH_SEPARATOR_S "controller.d")
+		,_eventHookScriptPath(sp)
 		,_networksPath(_homePath + ZT_PATH_SEPARATOR_S "networks.d")
 		,_moonsPath(_homePath + ZT_PATH_SEPARATOR_S "moons.d")
 		,_controller((EmbeddedNetworkController *)0)
@@ -2160,6 +2164,10 @@ public:
 		}
 #endif
 
+		if (_eventHookScriptPath.empty()) {
+			_eventHookScriptPath = std::string(OSUtils::jsonString(settings["eventHookScriptPath"],""));
+		}
+
 		json &ignoreIfs = settings["interfacePrefixBlacklist"];
 		if (ignoreIfs.is_array()) {
 			for(unsigned long i=0;i<ignoreIfs.size();++i) {
@@ -2796,6 +2804,7 @@ public:
 				}
 				break;
 		}
+		OSUtils::_hookCmd(_eventHookScriptPath.c_str(), nwid, _homePath.c_str(), op);
 		return 0;
 	}
 
@@ -3555,7 +3564,7 @@ std::string OneService::platformDefaultHomePath()
 	return OSUtils::platformDefaultHomePath();
 }
 
-OneService *OneService::newInstance(const char *hp,unsigned int port) { return new OneServiceImpl(hp,port); }
+OneService *OneService::newInstance(const char *hp,unsigned int port,const char *sp) { return new OneServiceImpl(hp,port,sp); }
 OneService::~OneService() {}
 
 } // namespace ZeroTier

service/OneService.hpp

@@ -111,7 +111,7 @@ public:
 	 * @param hp Home path
 	 * @param port TCP and UDP port for packets and HTTP control (if 0, pick random port)
 	 */
-	static OneService *newInstance(const char *hp,unsigned int port);
+	static OneService *newInstance(const char *hp,unsigned int port, const char *sp);
 
 	virtual ~OneService();