traefik/pkg/tcp/proxy.go
2020-11-13 12:48:04 +01:00

93 lines
2.1 KiB
Go

package tcp
import (
"io"
"net"
"time"
"github.com/traefik/traefik/v2/pkg/log"
)
// Proxy forwards a TCP request to a TCP service.
type Proxy struct {
address string
target *net.TCPAddr
terminationDelay time.Duration
refreshTarget bool
}
// NewProxy creates a new Proxy.
func NewProxy(address string, terminationDelay time.Duration) (*Proxy, error) {
tcpAddr, err := net.ResolveTCPAddr("tcp", address)
if err != nil {
return nil, err
}
// enable the refresh of the target only if the address in an IP
refreshTarget := false
if host, _, err := net.SplitHostPort(address); err == nil && net.ParseIP(host) == nil {
refreshTarget = true
}
return &Proxy{
address: address,
target: tcpAddr,
refreshTarget: refreshTarget,
terminationDelay: terminationDelay,
}, nil
}
// ServeTCP forwards the connection to a service.
func (p *Proxy) ServeTCP(conn WriteCloser) {
log.Debugf("Handling connection from %s", conn.RemoteAddr())
// needed because of e.g. server.trackedConnection
defer conn.Close()
if p.refreshTarget {
tcpAddr, err := net.ResolveTCPAddr("tcp", p.address)
if err != nil {
log.Errorf("Error resolving tcp address: %v", err)
return
}
p.target = tcpAddr
}
connBackend, err := net.DialTCP("tcp", nil, p.target)
if err != nil {
log.Errorf("Error while connection to backend: %v", err)
return
}
// maybe not needed, but just in case
defer connBackend.Close()
errChan := make(chan error)
go p.connCopy(conn, connBackend, errChan)
go p.connCopy(connBackend, conn, errChan)
err = <-errChan
if err != nil {
log.WithoutContext().Errorf("Error during connection: %v", err)
}
<-errChan
}
func (p Proxy) connCopy(dst, src WriteCloser, errCh chan error) {
_, err := io.Copy(dst, src)
errCh <- err
errClose := dst.CloseWrite()
if errClose != nil {
log.WithoutContext().Debugf("Error while terminating connection: %v", errClose)
return
}
if p.terminationDelay >= 0 {
err := dst.SetReadDeadline(time.Now().Add(p.terminationDelay))
if err != nil {
log.WithoutContext().Debugf("Error while setting deadline: %v", err)
}
}
}