/* * Copyright (c)2019 ZeroTier, Inc. * * Use of this software is governed by the Business Source License included * in the LICENSE.TXT file in the project's root directory. * * Change Date: 2023-01-01 * * On the date above, in accordance with the Business Source License, use * of this software will be governed by version 2.0 of the Apache License. */ /****/ #include "../node/Constants.hpp" #ifdef __LINUX__ #include "../node/Utils.hpp" #include "../node/Mutex.hpp" #include "../node/Dictionary.hpp" #include "OSUtils.hpp" #include "LinuxEthernetTap.hpp" #include "LinuxNetLink.hpp" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include // ff:ff:ff:ff:ff:ff with no ADI static const ZeroTier::MulticastGroup _blindWildcardMulticastGroup(ZeroTier::MAC(0xff),0); namespace ZeroTier { static Mutex __tapCreateLock; static const char _base32_chars[32] = { 'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z','2','3','4','5','6','7' }; static void _base32_5_to_8(const uint8_t *in,char *out) { out[0] = _base32_chars[(in[0]) >> 3]; out[1] = _base32_chars[(in[0] & 0x07) << 2 | (in[1] & 0xc0) >> 6]; out[2] = _base32_chars[(in[1] & 0x3e) >> 1]; out[3] = _base32_chars[(in[1] & 0x01) << 4 | (in[2] & 0xf0) >> 4]; out[4] = _base32_chars[(in[2] & 0x0f) << 1 | (in[3] & 0x80) >> 7]; out[5] = _base32_chars[(in[3] & 0x7c) >> 2]; out[6] = _base32_chars[(in[3] & 0x03) << 3 | (in[4] & 0xe0) >> 5]; out[7] = _base32_chars[(in[4] & 0x1f)]; } LinuxEthernetTap::LinuxEthernetTap( const char *homePath, const MAC &mac, unsigned int mtu, unsigned int metric, uint64_t nwid, const char *friendlyName, void (*handler)(void *,void *,uint64_t,const MAC &,const MAC &,unsigned int,unsigned int,const void *,unsigned int), void *arg) : _handler(handler), _arg(arg), _nwid(nwid), _homePath(homePath), _mtu(mtu), _fd(0), _enabled(true) { char procpath[128],nwids[32]; struct stat sbuf; // ensure netlink connection is started (void)LinuxNetLink::getInstance(); OSUtils::ztsnprintf(nwids,sizeof(nwids),"%.16llx",nwid); Mutex::Lock _l(__tapCreateLock); // create only one tap at a time, globally _fd = ::open("/dev/net/tun",O_RDWR); if (_fd <= 0) { _fd = ::open("/dev/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)); // Restore device names from legacy devicemap, but for new devices we use a base32-based canonical naming std::map globalDeviceMap; FILE *devmapf = fopen((_homePath + ZT_PATH_SEPARATOR_S + "devicemap").c_str(),"r"); if (devmapf) { char buf[256]; while (fgets(buf,sizeof(buf),devmapf)) { char *x = (char *)0; char *y = (char *)0; char *saveptr = (char *)0; for(char *f=Utils::stok(buf,"\r\n=",&saveptr);(f);f=Utils::stok((char *)0,"\r\n=",&saveptr)) { if (!x) x = f; else if (!y) y = f; else break; } if ((x)&&(y)&&(x[0])&&(y[0])) globalDeviceMap[x] = y; } fclose(devmapf); } bool recalledDevice = false; std::map::const_iterator gdmEntry = globalDeviceMap.find(nwids); if (gdmEntry != globalDeviceMap.end()) { Utils::scopy(ifr.ifr_name,sizeof(ifr.ifr_name),gdmEntry->second.c_str()); OSUtils::ztsnprintf(procpath,sizeof(procpath),"/proc/sys/net/ipv4/conf/%s",ifr.ifr_name); recalledDevice = (stat(procpath,&sbuf) != 0); } if (!recalledDevice) { #ifdef __SYNOLOGY__ int devno = 50; do { OSUtils::ztsnprintf(ifr.ifr_name,sizeof(ifr.ifr_name),"eth%d",devno++); OSUtils::ztsnprintf(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 #else uint64_t trial = 0; // incremented in the very unlikely event of a name collision with another network do { const uint64_t nwid40 = (nwid ^ (nwid >> 24)) + trial++; uint8_t tmp2[5]; char tmp3[11]; tmp2[0] = (uint8_t)((nwid40 >> 32) & 0xff); tmp2[1] = (uint8_t)((nwid40 >> 24) & 0xff); tmp2[2] = (uint8_t)((nwid40 >> 16) & 0xff); tmp2[3] = (uint8_t)((nwid40 >> 8) & 0xff); tmp2[4] = (uint8_t)(nwid40 & 0xff); tmp3[0] = 'z'; tmp3[1] = 't'; _base32_5_to_8(tmp2,tmp3 + 2); tmp3[10] = (char)0; memcpy(ifr.ifr_name,tmp3,11); OSUtils::ztsnprintf(procpath,sizeof(procpath),"/proc/sys/net/ipv4/conf/%s",ifr.ifr_name); } while (stat(procpath,&sbuf) == 0); #endif } 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); (void)::pipe(_shutdownSignalPipe); /* globalDeviceMap[nwids] = _dev; devmapf = fopen((_homePath + ZT_PATH_SEPARATOR_S + "devicemap").c_str(),"w"); if (devmapf) { gdmEntry = globalDeviceMap.begin(); while (gdmEntry != globalDeviceMap.end()) { fprintf(devmapf,"%s=%s\n",gdmEntry->first.c_str(),gdmEntry->second.c_str()); ++gdmEntry; } fclose(devmapf); } */ _thread = Thread::start(this); } LinuxEthernetTap::~LinuxEthernetTap() { (void)::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; } bool LinuxEthernetTap::enabled() const { return _enabled; } static bool ___removeIp(const std::string &_dev,const InetAddress &ip) { LinuxNetLink::getInstance().removeAddress(ip, _dev.c_str()); return true; } #ifdef __SYNOLOGY__ bool LinuxEthernetTap::addIpSyn(std::vector ips) { // Here we fill out interface config (ifcfg-dev) to prevent it from being killed std::string filepath = "/etc/sysconfig/network-scripts/ifcfg-"+_dev; std::string cfg_contents = "DEVICE="+_dev+"\nBOOTPROTO=static"; int ip4=0,ip6=0,ip4_tot=0,ip6_tot=0; for(int i=0; i<(int)ips.size(); i++) { if (ips[i].isV4()) ip4_tot++; else ip6_tot++; } // Assemble and write contents of ifcfg-dev file for(int i=0; i<(int)ips.size(); i++) { if (ips[i].isV4()) { char iptmp[64],iptmp2[64]; std::string numstr4 = ip4_tot > 1 ? std::to_string(ip4) : ""; cfg_contents += "\nIPADDR"+numstr4+"="+ips[i].toIpString(iptmp) + "\nNETMASK"+numstr4+"="+ips[i].netmask().toIpString(iptmp2)+"\n"; ip4++; } else { char iptmp[64],iptmp2[64]; std::string numstr6 = ip6_tot > 1 ? std::to_string(ip6) : ""; cfg_contents += "\nIPV6ADDR"+numstr6+"="+ips[i].toIpString(iptmp) + "\nNETMASK"+numstr6+"="+ips[i].netmask().toIpString(iptmp2)+"\n"; ip6++; } } OSUtils::writeFile(filepath.c_str(), cfg_contents.c_str(), cfg_contents.length()); // Finaly, add IPs for(int i=0; i<(int)ips.size(); i++){ LinuxNetLink::getInstance().addAddress(ips[i], _dev.c_str()); } return true; } #endif // __SYNOLOGY__ bool LinuxEthernetTap::addIp(const InetAddress &ip) { if (!ip) return false; std::vector allIps(ips()); if (std::binary_search(allIps.begin(),allIps.end(),ip)) return true; // Remove and reconfigure if address is the same but netmask is different for(std::vector::iterator i(allIps.begin());i!=allIps.end();++i) { if (i->ipsEqual(ip)) ___removeIp(_dev,*i); } LinuxNetLink::getInstance().addAddress(ip, _dev.c_str()); return true; } bool LinuxEthernetTap::removeIp(const InetAddress &ip) { if (!ip) return true; std::vector allIps(ips()); if (std::find(allIps.begin(),allIps.end(),ip) != allIps.end()) { if (___removeIp(_dev,ip)) return true; } return false; } std::vector LinuxEthernetTap::ips() const { struct ifaddrs *ifa = (struct ifaddrs *)0; if (getifaddrs(&ifa)) return std::vector(); std::vector 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.push_back(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.push_back(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); std::sort(r.begin(),r.end()); r.erase(std::unique(r.begin(),r.end()),r.end()); return r; } void LinuxEthernetTap::put(const MAC &from,const MAC &to,unsigned int etherType,const void *data,unsigned int len) { char putBuf[ZT_MAX_MTU + 64]; 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; (void)::write(_fd,putBuf,len); } } std::string LinuxEthernetTap::deviceName() const { return _dev; } void LinuxEthernetTap::setFriendlyName(const char *friendlyName) { } void LinuxEthernetTap::scanMulticastGroups(std::vector &added,std::vector &removed) { char *ptr,*ptr2; unsigned char mac[6]; std::vector 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.push_back(MulticastGroup(MAC(mac,6),0)); } } ::close(fd); } std::vector allIps(ips()); for(std::vector::iterator ip(allIps.begin());ip!=allIps.end();++ip) newGroups.push_back(MulticastGroup::deriveMulticastGroupForAddressResolution(*ip)); std::sort(newGroups.begin(),newGroups.end()); newGroups.erase(std::unique(newGroups.begin(),newGroups.end()),newGroups.end()); for(std::vector::iterator m(newGroups.begin());m!=newGroups.end();++m) { if (!std::binary_search(_multicastGroups.begin(),_multicastGroups.end(),*m)) added.push_back(*m); } for(std::vector::iterator m(_multicastGroups.begin());m!=_multicastGroups.end();++m) { if (!std::binary_search(newGroups.begin(),newGroups.end(),*m)) removed.push_back(*m); } _multicastGroups.swap(newGroups); } void LinuxEthernetTap::setMtu(unsigned int mtu) { if (_mtu != mtu) { _mtu = mtu; int sock = socket(AF_INET,SOCK_DGRAM,0); if (sock > 0) { struct ifreq ifr; memset(&ifr,0,sizeof(ifr)); ifr.ifr_ifru.ifru_mtu = (int)mtu; ioctl(sock,SIOCSIFMTU,(void *)&ifr); close(sock); } } } void LinuxEthernetTap::threadMain() throw() { fd_set readfds,nullfds; MAC to,from; int n,nfds,r; char getBuf[ZT_MAX_MTU + 64]; 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]); // TODO: VLAN support _handler(_arg,(void *)0,_nwid,from,to,etherType,0,(const void *)(getBuf + 14),r - 14); } r = 0; } } } } } } // namespace ZeroTier #endif // __LINUX__