route/lib/tunnel/tcpproxy.go

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package tunnel
import (
"fmt"
"net"
"git.xeserv.us/xena/route/lib/tunnel/proto"
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"github.com/koding/logging"
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)
var (
tpcLog = logging.NewLogger("tcp")
)
// TCPProxy forwards TCP streams.
//
// If port-based routing is used, LocalAddr or FetchLocalAddr field is required
// for tunneling to function properly.
// Otherwise you'll be forwarding traffic to random ports and this is usually not desired.
//
// If IP-based routing is used then tunnel server connection request is
// proxied to 127.0.0.1:incomingPort where incomingPort is control message LocalPort.
// Usually this is tunnel server's public exposed Port.
// This behaviour can be changed by setting LocalAddr or FetchLocalAddr.
// FetchLocalAddr takes precedence over LocalAddr.
type TCPProxy struct {
// LocalAddr defines the TCP address of the local server.
// This is optional if you want to specify a single TCP address.
LocalAddr string
// FetchLocalAddr is used for looking up TCP address of the server.
// This is optional if you want to specify a dynamic TCP address based on incommig port.
FetchLocalAddr func(port int) (string, error)
// Log is a custom logger that can be used for the proxy.
// If not set a "tcp" logger is used.
Log logging.Logger
}
// Proxy is a ProxyFunc.
func (p *TCPProxy) Proxy(remote net.Conn, msg *proto.ControlMessage) {
if msg.Protocol != proto.TCP {
panic("Proxy mismatch")
}
var log = p.log()
var port = msg.LocalPort
if port == 0 {
log.Warning("TCP proxy to port 0")
}
var localAddr = fmt.Sprintf("127.0.0.1:%d", port)
if p.LocalAddr != "" {
localAddr = p.LocalAddr
} else if p.FetchLocalAddr != nil {
l, err := p.FetchLocalAddr(msg.LocalPort)
if err != nil {
log.Warning("Failed to get custom local address: %s", err)
return
}
localAddr = l
}
log.Debug("Dialing local server: %q", localAddr)
local, err := net.DialTimeout("tcp", localAddr, defaultTimeout)
if err != nil {
log.Error("Dialing local server %q failed: %s", localAddr, err)
return
}
Join(local, remote, log)
}
func (p *TCPProxy) log() logging.Logger {
if p.Log != nil {
return p.Log
}
return tpcLog
}