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| package main
import (
"net"
"runtime"
"syscall"
)
const (
evListen = uint32((syscall.EPOLLET | syscall.EPOLLIN | syscall.EPOLLRDHUP) & 0xffffffff)
evClient = uint32((syscall.EPOLLET | syscall.EPOLLIN | syscall.EPOLLOUT | syscall.EPOLLRDHUP) & 0xffffffff)
evRead = uint32((syscall.EPOLLIN | syscall.EPOLLRDHUP | syscall.EPOLLERR) & 0xffffffff)
evWrite = uint32((syscall.EPOLLOUT | syscall.EPOLLHUP | syscall.EPOLLERR) & 0xffffffff)
)
func resolveSockAddr4(netaddr string) syscall.Sockaddr {
addr, err := net.ResolveTCPAddr("tcp4", netaddr)
if err != nil {
return nil
}
ip := addr.IP
if len(ip) == 0 {
ip = net.IPv4zero
}
sa4 := &syscall.SockaddrInet4{Port: addr.Port}
copy(sa4.Addr[:], ip.To4())
return sa4
}
type server struct {
epfd int
listenfd int
}
func (s *server) bind(fd int, ev uint32) error {
var e syscall.EpollEvent
syscall.SetNonblock(fd, true)
e.Events = ev
e.Fd = int32(fd)
return syscall.EpollCtl(s.epfd, syscall.EPOLL_CTL_ADD, fd, &e)
}
func (s *server) unbind(fd int) {
var e syscall.EpollEvent
syscall.EpollCtl(s.epfd, syscall.EPOLL_CTL_DEL, fd, &e)
}
func (s *server) init() (err error) {
s.epfd, err = syscall.EpollCreate1(syscall.EPOLL_CLOEXEC)
return
}
func (s *server) close() {
syscall.Close(s.listenfd)
syscall.Close(s.epfd)
}
func (s *server) listen(addr string) error {
lfd, err := syscall.Socket(syscall.AF_INET, syscall.SOCK_STREAM, syscall.IPPROTO_TCP)
if err != nil {
return err
}
ok := false
defer func() {
if !ok {
syscall.Close(lfd)
}
}()
err = syscall.Bind(lfd, resolveSockAddr4(addr))
if err != nil {
return err
}
s.bind(lfd, evListen)
err = syscall.Listen(lfd, syscall.SOMAXCONN)
if err != nil {
return err
}
s.listenfd = lfd
ok = true
return nil
}
func (s *server) poll(onEvent func(int, int)) error {
var events [64]syscall.EpollEvent
for {
n, err := syscall.EpollWait(s.epfd, events[:], -1)
if err != nil {
if err == syscall.EINTR {
continue
}
return err
}
for i := 0; i < n; i++ {
if s.listenfd == int(events[i].Fd) {
for {
clientfd, _, err := syscall.Accept(s.listenfd)
if err != nil {
if err != syscall.EAGAIN {
return err
}
break
}
s.bind(clientfd, evClient)
}
} else {
available := 0
if (events[i].Events & evRead) != 0 {
available |= 1
}
if (events[i].Events & evWrite) != 0 {
available |= 2
}
onEvent(int(events[i].Fd), available)
}
}
}
}
func main() {
s := server{}
err := s.init()
if err != nil {
panic(err)
}
defer s.close()
err = s.listen(":6126")
if err != nil {
panic(err)
}
type polldesp struct {
fd int
rw int
}
handler := func(ch <-chan polldesp) {
var buf [1024]byte
for pd := range ch {
fd := pd.fd
shouldClose := false
if (pd.rw & 1) != 0 {
for {
n, err := syscall.Read(fd, buf[:])
if n > 0 {
data := buf[:n]
n, err = syscall.Write(fd, data)
if err == nil {
err = syscall.Fsync(fd)
}
}
if n == 0 || err != nil {
if err == syscall.EAGAIN {
err = nil
} else {
shouldClose = true
}
break
}
}
}
if shouldClose {
s.unbind(fd)
syscall.Close(fd)
}
}
}
ncpu := runtime.NumCPU()
chs := make([]chan polldesp, ncpu)
err = s.poll(func(fd int, rw int) {
ch := chs[fd%ncpu]
if ch == nil {
ch = make(chan polldesp, 2)
chs[fd%ncpu] = ch
go handler(ch)
}
ch <- polldesp{fd, rw}
})
if err != nil {
panic(err)
}
}
|