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|
package forwarder
import (
"fmt"
"net"
"sync"
log "github.com/sirupsen/logrus"
"gvisor.dev/gvisor/pkg/tcpip"
"gvisor.dev/gvisor/pkg/tcpip/adapters/gonet"
"gvisor.dev/gvisor/pkg/tcpip/header"
"gvisor.dev/gvisor/pkg/tcpip/stack"
"gvisor.dev/gvisor/pkg/tcpip/transport/udp"
"gvisor.dev/gvisor/pkg/waiter"
)
func UDP(s *stack.Stack, nat map[tcpip.Address]tcpip.Address, natLock *sync.Mutex) *udp.Forwarder {
return udp.NewForwarder(s, func(r *udp.ForwarderRequest) {
localAddress := r.ID().LocalAddress
if linkLocal().Contains(localAddress) || localAddress == header.IPv4Broadcast {
return
}
natLock.Lock()
if replaced, ok := nat[localAddress]; ok {
localAddress = replaced
}
natLock.Unlock()
var wq waiter.Queue
ep, tcpErr := r.CreateEndpoint(&wq)
if tcpErr != nil {
if _, ok := tcpErr.(*tcpip.ErrConnectionRefused); ok {
// transient error
log.Debugf("r.CreateEndpoint() = %v", tcpErr)
} else {
log.Errorf("r.CreateEndpoint() = %v", tcpErr)
}
return
}
p, _ := NewUDPProxy(&autoStoppingListener{underlying: gonet.NewUDPConn(&wq, ep)}, func() (net.Conn, error) {
return net.Dial("udp", fmt.Sprintf("%s:%d", localAddress, r.ID().LocalPort))
})
go func() {
p.Run()
// note that at this point packets that are sent to the current forwarder session
// will be dropped. We will start processing the packets again when we get a new
// forwarder request.
ep.Close()
}()
})
}
|
