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httpmux.go
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httpmux.go
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package proxy
import (
"github.com/alphabetY/goflyway1/pkg/logg"
"errors"
"io"
"net"
"strings"
"time"
)
// prefetchReader can prefetch one byte from the reader before Read()
type prefetchReader struct {
src io.Reader
first byte
reseted bool
err error
timeout int
obpool *OneBytePool
}
func (ur *prefetchReader) readTimeout(buf []byte) (n int, err error) {
finish := make(chan bool, 1)
go func() {
n, err = ur.src.Read(buf)
finish <- true
}()
select {
case <-finish:
case <-time.After(time.Duration(ur.timeout) * time.Millisecond):
err = errors.New("i/o read timeout")
}
return
}
func (ur *prefetchReader) prefetch() (byte, error) {
buf := ur.obpool.Get()
defer ur.obpool.Free(buf)
n, err := ur.readTimeout(buf)
ur.err = err
if n == 1 {
ur.first = buf[0]
return buf[0], nil
}
return buf[0], err
}
func (ur *prefetchReader) Read(p []byte) (int, error) {
if ur.err != nil {
return 0, ur.err
}
if !ur.reseted {
p[0] = ur.first
xp := p[1:]
n, err := ur.src.Read(xp)
ur.reseted = true
return n + 1, err
}
return ur.src.Read(p)
}
type OneBytePool chan []byte
func NewOneBytePool(s int) *OneBytePool {
p := OneBytePool(make(chan []byte, s))
return &p
}
func (p *OneBytePool) Get() []byte {
select {
case buf := <-*p:
return buf
default:
return make([]byte, 1)
}
}
func (p *OneBytePool) Free(buf []byte) {
select {
case *p <- buf:
default:
}
}
type connWrapper struct {
net.Conn
sbuffer *prefetchReader
}
func (cw *connWrapper) Read(p []byte) (int, error) {
return cw.sbuffer.Read(p)
}
type listenerWrapper struct {
net.Listener
proxy *ProxyClient
httpConn connWrapper
socksConn connWrapper
obpool *OneBytePool
retry24 bool
}
func (l *listenerWrapper) Accept() (net.Conn, error) {
isC24Retried := false
CONTINUE:
c, err := l.Listener.Accept()
if err != nil || c == nil {
errs := err.Error()
if l.retry24 && strings.Contains(errs, "too many open files") && !isC24Retried {
// if this is the first time we encounter "too many open files"
// inform the daemon to aggresively close the old connections so we can try again
// normally error 24 is not that likely to happen in most of time
// even it did happen, you can increase the limit by ulimit -n
// UNLESS you are using macos, changing this number would be quite painful ;)
logg.D("encounter 'too many open files', start purging idle connections")
l.proxy.Cipher.IO.aggr <- true
<-l.proxy.Cipher.IO.aggr
isC24Retried = true
goto CONTINUE
}
logg.E("listener: ", err)
if isClosedConnErr(err) {
return nil, err
}
goto CONTINUE
}
wrapper := &connWrapper{
Conn: c,
sbuffer: &prefetchReader{
src: c,
obpool: l.obpool,
timeout: 2000, // 2 seconds
},
}
b, err := wrapper.sbuffer.prefetch()
if err != nil {
if err != io.EOF {
logg.E("prefetch err: ", err)
}
wrapper.Close()
goto CONTINUE
}
isC24Retried = false
switch b {
case 0x04, 0x05:
// we are accepting SOCKS4 in case it goes to the HTTP handler
go l.proxy.handleSocks(wrapper)
goto CONTINUE
default:
return wrapper, err
}
}