osnet -> osdep

osdep/LinuxEthernetTap.cpp

@@ -0,0 +1,424 @@
+/*
+ * ZeroTier One - Network Virtualization Everywhere
+ * Copyright (C) 2011-2015  ZeroTier, Inc.
+ *
+ * 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/>.
+ *
+ * --
+ *
+ * ZeroTier may be used and distributed under the terms of the GPLv3, which
+ * are available at: http://www.gnu.org/licenses/gpl-3.0.html
+ *
+ * If you would like to embed ZeroTier into a commercial application or
+ * redistribute it in a modified binary form, please contact ZeroTier Networks
+ * LLC. Start here: http://www.zerotier.com/
+ */
+
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <signal.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/ioctl.h>
+#include <sys/wait.h>
+#include <sys/select.h>
+#include <netinet/in.h>
+#include <net/if_arp.h>
+#include <arpa/inet.h>
+#include <linux/if.h>
+#include <linux/if_tun.h>
+#include <linux/if_addr.h>
+#include <linux/if_ether.h>
+#include <ifaddrs.h>
+
+#include <string>
+#include <map>
+#include <set>
+#include <algorithm>
+
+#include "../node/Constants.hpp"
+#include "../node/Utils.hpp"
+#include "../node/Mutex.hpp"
+#include "LinuxEthernetTap.hpp"
+
+// ff:ff:ff:ff:ff:ff with no ADI
+static const ZeroTier::MulticastGroup _blindWildcardMulticastGroup(ZeroTier::MAC(0xff),0);
+
+namespace ZeroTier {
+
+static Mutex __tapCreateLock;
+
+LinuxEthernetTap::LinuxEthernetTap(
+	const MAC &mac,
+	unsigned int mtu,
+	unsigned int metric,
+	uint64_t nwid,
+	const char *desiredDevice,
+	const char *friendlyName,
+	void (*handler)(void *,const MAC &,const MAC &,unsigned int,const Buffer<4096> &),
+	void *arg) :
+	EthernetTap("LinuxEthernetTap",mac,mtu,metric),
+	_handler(handler),
+	_arg(arg),
+	_fd(0),
+	_enabled(true)
+{
+	char procpath[128];
+	struct stat sbuf;
+
+	Mutex::Lock _l(__tapCreateLock); // create only one tap at a time, globally
+
+	if (mtu > 2800)
+		throw std::runtime_error("max tap MTU is 2800");
+
+	_fd = ::open("/dev/net/tun",O_RDWR);
+	if (_fd <= 0)
+		throw std::runtime_error(std::string("could not open TUN/TAP device: ") + strerror(errno));
+
+	struct ifreq ifr;
+	memset(&ifr,0,sizeof(ifr));
+
+	// Try to recall our last device name, or pick an unused one if that fails.
+	bool recalledDevice = false;
+	if ((desiredDevice)&&(desiredDevice[0])) {
+		Utils::scopy(ifr.ifr_name,sizeof(ifr.ifr_name),desiredDevice);
+		Utils::snprintf(procpath,sizeof(procpath),"/proc/sys/net/ipv4/conf/%s",ifr.ifr_name);
+		recalledDevice = (stat(procpath,&sbuf) != 0);
+	}
+	if (!recalledDevice) {
+		int devno = 0;
+		do {
+			Utils::snprintf(ifr.ifr_name,sizeof(ifr.ifr_name),"zt%d",devno++);
+			Utils::snprintf(procpath,sizeof(procpath),"/proc/sys/net/ipv4/conf/%s",ifr.ifr_name);
+		} while (stat(procpath,&sbuf) == 0); // try zt#++ until we find one that does not exist
+	}
+
+	ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
+	if (ioctl(_fd,TUNSETIFF,(void *)&ifr) < 0) {
+		::close(_fd);
+		throw std::runtime_error("unable to configure TUN/TAP device for TAP operation");
+	}
+
+	_dev = ifr.ifr_name;
+
+	::ioctl(_fd,TUNSETPERSIST,0); // valgrind may generate a false alarm here
+
+	// Open an arbitrary socket to talk to netlink
+	int sock = socket(AF_INET,SOCK_DGRAM,0);
+	if (sock <= 0) {
+		::close(_fd);
+		throw std::runtime_error("unable to open netlink socket");
+	}
+
+	// Set MAC address
+	ifr.ifr_ifru.ifru_hwaddr.sa_family = ARPHRD_ETHER;
+	mac.copyTo(ifr.ifr_ifru.ifru_hwaddr.sa_data,6);
+	if (ioctl(sock,SIOCSIFHWADDR,(void *)&ifr) < 0) {
+		::close(_fd);
+		::close(sock);
+		throw std::runtime_error("unable to configure TAP hardware (MAC) address");
+		return;
+	}
+
+	// Set MTU
+	ifr.ifr_ifru.ifru_mtu = (int)mtu;
+	if (ioctl(sock,SIOCSIFMTU,(void *)&ifr) < 0) {
+		::close(_fd);
+		::close(sock);
+		throw std::runtime_error("unable to configure TAP MTU");
+	}
+
+	if (fcntl(_fd,F_SETFL,fcntl(_fd,F_GETFL) & ~O_NONBLOCK) == -1) {
+		::close(_fd);
+		throw std::runtime_error("unable to set flags on file descriptor for TAP device");
+	}
+
+	/* Bring interface up */
+	if (ioctl(sock,SIOCGIFFLAGS,(void *)&ifr) < 0) {
+		::close(_fd);
+		::close(sock);
+		throw std::runtime_error("unable to get TAP interface flags");
+	}
+	ifr.ifr_flags |= IFF_UP;
+	if (ioctl(sock,SIOCSIFFLAGS,(void *)&ifr) < 0) {
+		::close(_fd);
+		::close(sock);
+		throw std::runtime_error("unable to set TAP interface flags");
+	}
+
+	::close(sock);
+
+	// Set close-on-exec so that devices cannot persist if we fork/exec for update
+	::fcntl(_fd,F_SETFD,fcntl(_fd,F_GETFD) | FD_CLOEXEC);
+
+	::pipe(_shutdownSignalPipe);
+
+	_thread = Thread::start(this);
+}
+
+LinuxEthernetTap::~LinuxEthernetTap()
+{
+	::write(_shutdownSignalPipe[1],"\0",1); // causes thread to exit
+	Thread::join(_thread);
+	::close(_fd);
+	::close(_shutdownSignalPipe[0]);
+	::close(_shutdownSignalPipe[1]);
+}
+
+void LinuxEthernetTap::setEnabled(bool en)
+{
+	_enabled = en;
+	// TODO: interface status change
+}
+
+bool LinuxEthernetTap::enabled() const
+{
+	return _enabled;
+}
+
+static bool ___removeIp(const std::string &_dev,const InetAddress &ip)
+{
+	long cpid = (long)vfork();
+	if (cpid == 0) {
+		Utils::redirectUnixOutputs("/dev/null",(const char *)0);
+		::execl("/sbin/ip","/sbin/ip","addr","del",ip.toString().c_str(),"dev",_dev.c_str(),(const char *)0);
+		::execl("/usr/sbin/ip","/usr/sbin/ip","addr","del",ip.toString().c_str(),"dev",_dev.c_str(),(const char *)0);
+		::_exit(-1);
+	} else {
+		int exitcode = -1;
+		::waitpid(cpid,&exitcode,0);
+		return (exitcode == 0);
+	}
+}
+
+bool LinuxEthernetTap::addIP(const InetAddress &ip)
+{
+	if (!ip)
+		return false;
+	std::set<InetAddress> allIps(ips());
+	if (allIps.count(ip) > 0)
+		return true;
+
+	// Remove and reconfigure if address is the same but netmask is different
+	for(std::set<InetAddress>::iterator i(allIps.begin());i!=allIps.end();++i) {
+		if (i->ipsEqual(ip))
+			___removeIp(_dev,*i);
+	}
+
+	long cpid = (long)vfork();
+	if (cpid == 0) {
+		Utils::redirectUnixOutputs("/dev/null",(const char *)0);
+		if (ip.isV4()) {
+			::execl("/sbin/ip","/sbin/ip","addr","add",ip.toString().c_str(),"broadcast",ip.broadcast().toIpString().c_str(),"dev",_dev.c_str(),(const char *)0);
+			::execl("/usr/sbin/ip","/usr/sbin/ip","addr","add",ip.toString().c_str(),"broadcast",ip.broadcast().toIpString().c_str(),"dev",_dev.c_str(),(const char *)0);
+		} else {
+			::execl("/sbin/ip","/sbin/ip","addr","add",ip.toString().c_str(),"dev",_dev.c_str(),(const char *)0);
+			::execl("/usr/sbin/ip","/usr/sbin/ip","addr","add",ip.toString().c_str(),"dev",_dev.c_str(),(const char *)0);
+		}
+		::_exit(-1);
+	} else if (cpid > 0) {
+		int exitcode = -1;
+		::waitpid(cpid,&exitcode,0);
+		return (exitcode == 0);
+	}
+
+	return false;
+}
+
+bool LinuxEthernetTap::removeIP(const InetAddress &ip)
+{
+	if (ips().count(ip) > 0) {
+		if (___removeIp(_dev,ip))
+			return true;
+	}
+	return false;
+}
+
+std::set<InetAddress> LinuxEthernetTap::ips() const
+{
+	struct ifaddrs *ifa = (struct ifaddrs *)0;
+	if (getifaddrs(&ifa))
+		return std::set<InetAddress>();
+
+	std::set<InetAddress> r;
+
+	struct ifaddrs *p = ifa;
+	while (p) {
+		if ((!strcmp(p->ifa_name,_dev.c_str()))&&(p->ifa_addr)&&(p->ifa_netmask)&&(p->ifa_addr->sa_family == p->ifa_netmask->sa_family)) {
+			switch(p->ifa_addr->sa_family) {
+				case AF_INET: {
+					struct sockaddr_in *sin = (struct sockaddr_in *)p->ifa_addr;
+					struct sockaddr_in *nm = (struct sockaddr_in *)p->ifa_netmask;
+					r.insert(InetAddress(&(sin->sin_addr.s_addr),4,Utils::countBits((uint32_t)nm->sin_addr.s_addr)));
+				}	break;
+				case AF_INET6: {
+					struct sockaddr_in6 *sin = (struct sockaddr_in6 *)p->ifa_addr;
+					struct sockaddr_in6 *nm = (struct sockaddr_in6 *)p->ifa_netmask;
+					uint32_t b[4];
+					memcpy(b,nm->sin6_addr.s6_addr,sizeof(b));
+					r.insert(InetAddress(sin->sin6_addr.s6_addr,16,Utils::countBits(b[0]) + Utils::countBits(b[1]) + Utils::countBits(b[2]) + Utils::countBits(b[3])));
+				}	break;
+			}
+		}
+		p = p->ifa_next;
+	}
+
+	if (ifa)
+		freeifaddrs(ifa);
+
+	return r;
+}
+
+void LinuxEthernetTap::put(const MAC &from,const MAC &to,unsigned int etherType,const void *data,unsigned int len)
+{
+	char putBuf[8194];
+	if ((_fd > 0)&&(len <= _mtu)&&(_enabled)) {
+		to.copyTo(putBuf,6);
+		from.copyTo(putBuf + 6,6);
+		*((uint16_t *)(putBuf + 12)) = htons((uint16_t)etherType);
+		memcpy(putBuf + 14,data,len);
+		len += 14;
+		::write(_fd,putBuf,len);
+	}
+}
+
+std::string LinuxEthernetTap::deviceName() const
+{
+	return _dev;
+}
+
+void LinuxEthernetTap::setFriendlyName(const char *friendlyName)
+{
+}
+
+bool LinuxEthernetTap::updateMulticastGroups(std::set<MulticastGroup> &groups)
+{
+	char *ptr,*ptr2;
+	unsigned char mac[6];
+	std::set<MulticastGroup> newGroups;
+
+	int fd = ::open("/proc/net/dev_mcast",O_RDONLY);
+	if (fd > 0) {
+		char buf[131072];
+		int n = (int)::read(fd,buf,sizeof(buf));
+		if ((n > 0)&&(n < (int)sizeof(buf))) {
+			buf[n] = (char)0;
+			for(char *l=strtok_r(buf,"\r\n",&ptr);(l);l=strtok_r((char *)0,"\r\n",&ptr)) {
+				int fno = 0;
+				char *devname = (char *)0;
+				char *mcastmac = (char *)0;
+				for(char *f=strtok_r(l," \t",&ptr2);(f);f=strtok_r((char *)0," \t",&ptr2)) {
+					if (fno == 1)
+						devname = f;
+					else if (fno == 4)
+						mcastmac = f;
+					++fno;
+				}
+				if ((devname)&&(!strcmp(devname,_dev.c_str()))&&(mcastmac)&&(Utils::unhex(mcastmac,mac,6) == 6))
+					newGroups.insert(MulticastGroup(MAC(mac,6),0));
+			}
+		}
+		::close(fd);
+	}
+
+	{
+		std::set<InetAddress> allIps(ips());
+		for(std::set<InetAddress>::const_iterator i(allIps.begin());i!=allIps.end();++i)
+			newGroups.insert(MulticastGroup::deriveMulticastGroupForAddressResolution(*i));
+	}
+
+	bool changed = false;
+
+	for(std::set<MulticastGroup>::iterator mg(newGroups.begin());mg!=newGroups.end();++mg) {
+		if (!groups.count(*mg)) {
+			groups.insert(*mg);
+			changed = true;
+		}
+	}
+	for(std::set<MulticastGroup>::iterator mg(groups.begin());mg!=groups.end();) {
+		if ((!newGroups.count(*mg))&&(*mg != _blindWildcardMulticastGroup)) {
+			groups.erase(mg++);
+			changed = true;
+		} else ++mg;
+	}
+
+	return changed;
+}
+
+bool LinuxEthernetTap::injectPacketFromHost(const MAC &from,const MAC &to,unsigned int etherType,const void *data,unsigned int len)
+{
+	return false;
+}
+
+void LinuxEthernetTap::threadMain()
+	throw()
+{
+	fd_set readfds,nullfds;
+	MAC to,from;
+	int n,nfds,r;
+	char getBuf[8194];
+	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);
+	nfds = (int)std::max(_shutdownSignalPipe[0],_fd) + 1;
+
+	r = 0;
+	for(;;) {
+		FD_SET(_shutdownSignalPipe[0],&readfds);
+		FD_SET(_fd,&readfds);
+		select(nfds,&readfds,&nullfds,&nullfds,(struct timeval *)0);
+
+		if (FD_ISSET(_shutdownSignalPipe[0],&readfds)) // writes to shutdown pipe terminate thread
+			break;
+
+		if (FD_ISSET(_fd,&readfds)) {
+			n = (int)::read(_fd,getBuf + r,sizeof(getBuf) - r);
+			if (n < 0) {
+				if ((errno != EINTR)&&(errno != ETIMEDOUT))
+					break;
+			} else {
+				// Some tap drivers like to send the ethernet frame and the
+				// payload in two chunks, so handle that by accumulating
+				// data until we have at least a frame.
+				r += n;
+				if (r > 14) {
+					if (r > ((int)_mtu + 14)) // sanity check for weird TAP behavior on some platforms
+						r = _mtu + 14;
+
+					if (_enabled) {
+						to.setTo(getBuf,6);
+						from.setTo(getBuf + 6,6);
+						unsigned int etherType = ntohs(((const uint16_t *)getBuf)[6]);
+						data.copyFrom(getBuf + 14,(unsigned int)r - 14);
+						_handler(_arg,from,to,etherType,data);
+					}
+
+					r = 0;
+				}
+			}
+		}
+	}
+}
+
+} // namespace ZeroTier