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Diffstat (limited to 'osdep/LinuxEthernetTap.cpp')
| -rw-r--r-- | osdep/LinuxEthernetTap.cpp | 424 |
1 files changed, 424 insertions, 0 deletions
diff --git a/osdep/LinuxEthernetTap.cpp b/osdep/LinuxEthernetTap.cpp new file mode 100644 index 00000000..ee89159e --- /dev/null +++ b/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 |