Split Linux tap receive into two threads: one reader, one processor.

This commit is contained in:
Adam Ierymenko 2020-11-16 21:40:25 -05:00
parent 5282e06fd4
commit 2da162bed7
No known key found for this signature in database
GPG Key ID: C8877CF2D7A5D7F3
3 changed files with 171 additions and 114 deletions

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@ -18,8 +18,8 @@
#include <mutex>
#include <condition_variable>
#include <chrono>
#include "Thread.hpp"
#include <atomic>
#include <vector>
namespace ZeroTier {
@ -67,7 +67,8 @@ public:
inline bool get(T &value)
{
std::unique_lock<std::mutex> lock(m);
if (!r) return false;
if (!r)
return false;
while (q.empty()) {
c.wait(lock);
if (!r) {
@ -81,6 +82,16 @@ public:
return true;
}
inline std::vector<T> drain()
{
std::vector<T> v;
while (!q.empty()) {
v.push_back(q.front());
q.pop();
}
return v;
}
enum TimedWaitResult
{
OK,
@ -92,7 +103,8 @@ public:
{
const std::chrono::milliseconds ms2{ms};
std::unique_lock<std::mutex> lock(m);
if (!r) return STOP;
if (!r)
return STOP;
while (q.empty()) {
if (c.wait_for(lock,ms2) == std::cv_status::timeout)
return ((r) ? TIMED_OUT : STOP);
@ -105,10 +117,10 @@ public:
}
private:
volatile bool r;
std::queue<T> q;
mutable std::mutex m;
mutable std::condition_variable c,gc;
std::atomic_bool r;
};
} // namespace ZeroTier

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@ -11,6 +11,10 @@
*/
/****/
#ifdef __GNUC__
#pragma GCC diagnostic ignored "-Wrestrict"
#endif
#include "../node/Constants.hpp"
#ifdef __LINUX__
@ -52,6 +56,8 @@
#define IFNAMSIZ 16
#endif
#define ZT_TAP_BUF_SIZE 16384
// ff:ff:ff:ff:ff:ff with no ADI
static const ZeroTier::MulticastGroup _blindWildcardMulticastGroup(ZeroTier::MAC(0xff),0);
@ -177,16 +183,153 @@ LinuxEthernetTap::LinuxEthernetTap(
(void)::pipe(_shutdownSignalPipe);
_thread = Thread::start(this);
_tapReaderThread = std::thread([this]{
fd_set readfds,nullfds;
int n,nfds,r;
void *buf = nullptr;
usleep(100000);
{
struct ifreq ifr;
memset(&ifr,0,sizeof(ifr));
strcpy(ifr.ifr_name,_dev.c_str());
const int sock = socket(AF_INET,SOCK_DGRAM,0);
if (sock <= 0)
return;
if (ioctl(sock,SIOCGIFFLAGS,(void *)&ifr) < 0) {
::close(sock);
printf("WARNING: ioctl() failed setting up Linux tap device (bring interface up)\n");
return;
}
ifr.ifr_flags |= IFF_UP;
if (ioctl(sock,SIOCSIFFLAGS,(void *)&ifr) < 0) {
::close(sock);
printf("WARNING: ioctl() failed setting up Linux tap device (bring interface up)\n");
return;
}
usleep(500000);
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(sock);
printf("WARNING: ioctl() failed setting up Linux tap device (set MAC)\n");
return;
}
ifr.ifr_ifru.ifru_mtu = (int)_mtu;
if (ioctl(sock,SIOCSIFMTU,(void *)&ifr) < 0) {
::close(sock);
printf("WARNING: ioctl() failed setting up Linux tap device (set MTU)\n");
return;
}
fcntl(_fd,F_SETFL,O_NONBLOCK);
::close(sock);
}
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)) {
for(int x=0;x<64;++x) {
if (!buf) {
std::lock_guard<std::mutex> l(_buffers_l);
if (_buffers.empty()) {
buf = malloc(ZT_TAP_BUF_SIZE);
if (!buf)
break;
} else {
buf = _buffers.back();
_buffers.pop_back();
}
}
n = (int)::read(_fd,reinterpret_cast<uint8_t *>(buf) + r,ZT_TAP_BUF_SIZE - r);
if (n < 0) {
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) {
_tapq.post(std::pair<void *,int>(buf,r));
buf = nullptr;
/*
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;
}
}
}
}
}
});
_tapProcessorThread = std::thread([this] {
MAC to,from;
std::pair<void *,int> qi;
while (_tapq.get(qi)) {
uint8_t *const b = reinterpret_cast<uint8_t *>(qi.first);
if (b) {
to.setTo(b, 6);
from.setTo(b + 6, 6);
unsigned int etherType = Utils::ntoh(((const uint16_t *)b)[6]);
_handler(_arg, nullptr, _nwid, from, to, etherType, 0, (const void *)(b + 14),(unsigned int)(qi.second - 14));
{
std::lock_guard<std::mutex> l(_buffers_l);
_buffers.push_back(qi.first);
}
} else break;
}
});
}
LinuxEthernetTap::~LinuxEthernetTap()
{
(void)::write(_shutdownSignalPipe[1],"\0",1); // causes thread to exit
Thread::join(_thread);
_tapq.post(std::pair<void *,int>(nullptr,0));
::close(_fd);
::close(_shutdownSignalPipe[0]);
::close(_shutdownSignalPipe[1]);
_tapReaderThread.join();
_tapProcessorThread.join();
for(std::vector<void *>::iterator i(_buffers.begin());i!=_buffers.end();++i)
free(*i);
std::vector< std::pair<void *,int> > dv(_tapq.drain());
for(std::vector< std::pair<void *,int> >::iterator i(dv.begin());i!=dv.end();++i) {
if (i->first)
free(i->first);
}
}
void LinuxEthernetTap::setEnabled(bool en)
@ -400,107 +543,6 @@ void LinuxEthernetTap::setMtu(unsigned int mtu)
}
}
void LinuxEthernetTap::threadMain()
throw()
{
fd_set readfds,nullfds;
MAC to,from;
int n,nfds,r;
char getBuf[ZT_MAX_MTU + 64];
Thread::sleep(100);
{
struct ifreq ifr;
memset(&ifr,0,sizeof(ifr));
strcpy(ifr.ifr_name,_dev.c_str());
const int sock = socket(AF_INET,SOCK_DGRAM,0);
if (sock <= 0)
return;
if (ioctl(sock,SIOCGIFFLAGS,(void *)&ifr) < 0) {
::close(sock);
printf("WARNING: ioctl() failed setting up Linux tap device (bring interface up)\n");
return;
}
ifr.ifr_flags |= IFF_UP;
if (ioctl(sock,SIOCSIFFLAGS,(void *)&ifr) < 0) {
::close(sock);
printf("WARNING: ioctl() failed setting up Linux tap device (bring interface up)\n");
return;
}
Thread::sleep(500);
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(sock);
printf("WARNING: ioctl() failed setting up Linux tap device (set MAC)\n");
return;
}
ifr.ifr_ifru.ifru_mtu = (int)_mtu;
if (ioctl(sock,SIOCSIFMTU,(void *)&ifr) < 0) {
::close(sock);
printf("WARNING: ioctl() failed setting up Linux tap device (set MTU)\n");
return;
}
if (fcntl(_fd,F_SETFL,O_NONBLOCK) == -1) {
::close(sock);
printf("WARNING: ioctl() failed setting up Linux tap device (set non-blocking)\n");
return;
}
::close(sock);
}
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)) {
for(int x=0;x<64;++x) {
n = (int)::read(_fd,getBuf + r,sizeof(getBuf) - r);
if (n < 0) {
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__

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@ -21,10 +21,12 @@
#include <vector>
#include <stdexcept>
#include <atomic>
#include <array>
#include <thread>
#include <mutex>
#include "../node/MulticastGroup.hpp"
#include "Thread.hpp"
#include "EthernetTap.hpp"
#include "BlockingQueue.hpp"
namespace ZeroTier {
@ -56,15 +58,11 @@ public:
virtual void setMtu(unsigned int mtu);
virtual void setDns(const char *domain, const std::vector<InetAddress> &servers) {}
void threadMain()
throw();
private:
void (*_handler)(void *,void *,uint64_t,const MAC &,const MAC &,unsigned int,unsigned int,const void *,unsigned int);
void *_arg;
uint64_t _nwid;
MAC _mac;
Thread _thread;
std::string _homePath;
std::string _dev;
std::vector<MulticastGroup> _multicastGroups;
@ -72,6 +70,11 @@ private:
int _fd;
int _shutdownSignalPipe[2];
std::atomic_bool _enabled;
std::thread _tapReaderThread;
std::thread _tapProcessorThread;
std::mutex _buffers_l;
std::vector<void *> _buffers;
BlockingQueue< std::pair<void *,int> > _tapq;
};
} // namespace ZeroTier