92 lines
2.3 KiB
Go
92 lines
2.3 KiB
Go
// Copyright 2024 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package nat
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import (
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"fmt"
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"net"
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"time"
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"github.com/pion/stun/v2"
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)
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// The code are from erigon p2p/nat/nat_stun.go
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// This stun server is part of the mainnet infrastructure.
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// The addr are from https://github.com/ethereum/trin/blob/master/portalnet/src/socket.rs
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const STUNDefaultServerAddr = "159.223.0.83:3478"
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type STUN struct {
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serverAddr *net.UDPAddr
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}
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func NewSTUN(serverAddr string) (Interface, error) {
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if serverAddr == "default" {
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serverAddr = STUNDefaultServerAddr
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}
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addr, err := net.ResolveUDPAddr("udp4", serverAddr)
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if err != nil {
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return nil, err
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}
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return STUN{serverAddr: addr}, nil
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}
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func (s STUN) String() string {
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return fmt.Sprintf("STUN(%s)", s.serverAddr)
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}
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func (STUN) SupportsMapping() bool {
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return false
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}
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func (STUN) AddMapping(protocol string, extport, intport int, name string, lifetime time.Duration) (uint16, error) {
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return uint16(extport), nil
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}
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func (STUN) DeleteMapping(string, int, int) error {
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return nil
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}
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func (s STUN) ExternalIP() (net.IP, error) {
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conn, err := stun.Dial("udp4", s.serverAddr.String())
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if err != nil {
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return nil, err
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}
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defer conn.Close()
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message, err := stun.Build(stun.TransactionID, stun.BindingRequest)
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if err != nil {
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return nil, err
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}
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var response *stun.Event
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err = conn.Do(message, func(event stun.Event) {
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response = &event
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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 response.Error != nil {
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return nil, response.Error
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}
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var mappedAddr stun.XORMappedAddress
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if err := mappedAddr.GetFrom(response.Message); err != nil {
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return nil, err
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}
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return mappedAddr.IP, nil
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}
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