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udp.go
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udp.go
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package redirect
import (
"errors"
"fmt"
"github.com/wsrf16/swiss/netkit/tun2socks/ctun2socks/core"
"github.com/wsrf16/swiss/sugar/logo"
"net"
"sync"
"time"
)
type udpHandler struct {
sync.Mutex
timeout time.Duration
udpConns map[core.UDPConn]*net.UDPConn
udpTargetAddrs map[core.UDPConn]*net.UDPAddr
target string
}
func NewUDPHandler(target string, timeout time.Duration) core.UDPConnHandler {
return &udpHandler{
timeout: timeout,
udpConns: make(map[core.UDPConn]*net.UDPConn, 8),
udpTargetAddrs: make(map[core.UDPConn]*net.UDPAddr, 8),
target: target,
}
}
func (h *udpHandler) fetchUDPInput(conn core.UDPConn, pc *net.UDPConn) {
buf := core.NewBytes(core.BufSize)
defer func() {
h.Close(conn)
core.FreeBytes(buf)
}()
for {
pc.SetDeadline(time.Now().Add(h.timeout))
n, addr, err := pc.ReadFromUDP(buf)
if err != nil {
// log.Printf("failed to read UDP data from remote: %v", err)
return
}
_, err = conn.WriteFrom(buf[:n], addr)
if err != nil {
logo.Wf("failed to write UDP data to TUN")
return
}
}
}
func (h *udpHandler) Connect(conn core.UDPConn, target *net.UDPAddr) error {
bindAddr := &net.UDPAddr{IP: nil, Port: 0}
pc, err := net.ListenUDP("udp", bindAddr)
if err != nil {
logo.Ef("failed to bind udp address")
return err
}
tgtAddr, _ := net.ResolveUDPAddr("udp", h.target)
h.Lock()
h.udpTargetAddrs[conn] = tgtAddr
h.udpConns[conn] = pc
h.Unlock()
go h.fetchUDPInput(conn, pc)
logo.If("new proxy connection for proxyAddress: %s:%s", target.Network(), target.String())
return nil
}
func (h *udpHandler) ReceiveTo(conn core.UDPConn, data []byte, addr *net.UDPAddr) error {
h.Lock()
pc, ok1 := h.udpConns[conn]
tgtAddr, ok2 := h.udpTargetAddrs[conn]
h.Unlock()
if ok1 && ok2 {
_, err := pc.WriteToUDP(data, tgtAddr)
if err != nil {
logo.Wf("failed to write UDP payload to SOCKS5 server: %v", err)
return errors.New("failed to write UDP data")
}
return nil
} else {
return errors.New(fmt.Sprintf("proxy connection %v->%v does not exists", conn.LocalAddr(), addr))
}
}
func (h *udpHandler) Close(conn core.UDPConn) {
conn.Close()
h.Lock()
defer h.Unlock()
if _, ok := h.udpTargetAddrs[conn]; ok {
delete(h.udpTargetAddrs, conn)
}
if pc, ok := h.udpConns[conn]; ok {
pc.Close()
delete(h.udpConns, conn)
}
}