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bolucat
109 lines
2.5 KiB
Go
109 lines
2.5 KiB
Go
// Copyright (c) 2016-present Cloud <cloud@txthinking.com>
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//
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// This program is free software; you can redistribute it and/or
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// modify it under the terms of version 3 of the GNU General Public
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// License as published by the Free Software Foundation.
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//
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// This program is distributed in the hope that it will be useful, but
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// WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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// General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program. If not, see <https://www.gnu.org/licenses/>.
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package brook
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import (
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"net"
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"strings"
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"sync"
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)
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type NATTable struct {
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Table map[string]string
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Lock *sync.Mutex
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}
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var NAT = &NATTable{
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Table: map[string]string{},
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Lock: &sync.Mutex{},
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}
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func (n *NATTable) Set(src, dst, addr string) {
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n.Lock.Lock()
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defer n.Lock.Unlock()
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n.Table[src+dst] = addr
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}
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func (n *NATTable) Get(src, dst string) string {
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n.Lock.Lock()
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defer n.Lock.Unlock()
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s, _ := n.Table[src+dst]
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return s
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}
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func (n *NATTable) Reset() {
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n.Lock.Lock()
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defer n.Lock.Unlock()
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n.Table = map[string]string{}
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}
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var NATDial func(network string, src, dst, addr string) (net.Conn, error) = func(network string, src, dst, addr string) (net.Conn, error) {
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s := NAT.Get(src, dst)
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var c net.Conn
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var err error
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if network == "tcp" {
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c, err = DialTCP(network, s, addr)
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}
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if network == "udp" {
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c, err = DialUDP(network, s, addr)
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}
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if err != nil {
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if !strings.Contains(err.Error(), "address already in use") && !strings.Contains(err.Error(), "assign requested address") {
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return nil, err
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}
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if network == "tcp" {
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c, err = DialTCP(network, "", addr)
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}
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if network == "udp" {
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c, err = DialUDP(network, "", addr)
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}
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s = ""
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}
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if err != nil {
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return nil, err
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}
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if s == "" {
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NAT.Set(src, dst, c.LocalAddr().String())
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}
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return c, nil
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}
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var NATListenUDP func(network string, src, dst string) (*net.UDPConn, error) = func(network string, src, dst string) (*net.UDPConn, error) {
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var laddr *net.UDPAddr
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s := NAT.Get(src, dst)
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if s != "" {
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var err error
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laddr, err = net.ResolveUDPAddr("udp", s)
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if err != nil {
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return nil, err
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}
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}
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c, err := ListenUDP("udp", laddr)
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if err != nil {
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if !strings.Contains(err.Error(), "address already in use") && !strings.Contains(err.Error(), "assign requested address") {
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return nil, err
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}
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c, err = ListenUDP("udp", nil)
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s = ""
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}
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if err != nil {
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return nil, err
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}
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if s == "" {
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NAT.Set(src, dst, c.LocalAddr().String())
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}
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return c, nil
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}
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