73 lines
1.9 KiB
Go
73 lines
1.9 KiB
Go
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// SPDX-FileCopyrightText: 2023 The Pion community <https://pion.ly>
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// SPDX-License-Identifier: MIT
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// Package stun contains ICE specific STUN code
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package stun
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import (
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"errors"
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"fmt"
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"net"
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"time"
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"github.com/pion/stun"
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)
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var (
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errGetXorMappedAddrResponse = errors.New("failed to get XOR-MAPPED-ADDRESS response")
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errMismatchUsername = errors.New("username mismatch")
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)
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// GetXORMappedAddr initiates a STUN requests to serverAddr using conn, reads the response and returns
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// the XORMappedAddress returned by the STUN server.
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func GetXORMappedAddr(conn net.PacketConn, serverAddr net.Addr, timeout time.Duration) (*stun.XORMappedAddress, error) {
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if timeout > 0 {
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if err := conn.SetReadDeadline(time.Now().Add(timeout)); err != nil {
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return nil, err
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}
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// Reset timeout after completion
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defer conn.SetReadDeadline(time.Time{}) //nolint:errcheck
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}
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req, err := stun.Build(stun.BindingRequest, stun.TransactionID)
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if err != nil {
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return nil, err
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}
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if _, err = conn.WriteTo(req.Raw, serverAddr); err != nil {
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return nil, err
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}
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const maxMessageSize = 1280
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buf := make([]byte, maxMessageSize)
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n, _, err := conn.ReadFrom(buf)
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if err != nil {
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return nil, err
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}
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res := &stun.Message{Raw: buf[:n]}
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if err = res.Decode(); err != nil {
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return nil, err
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}
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var addr stun.XORMappedAddress
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if err = addr.GetFrom(res); err != nil {
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return nil, fmt.Errorf("%w: %v", errGetXorMappedAddrResponse, err) //nolint:errorlint
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}
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return &addr, nil
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}
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// AssertUsername checks that the given STUN message m has a USERNAME attribute with a given value
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func AssertUsername(m *stun.Message, expectedUsername string) error {
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var username stun.Username
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if err := username.GetFrom(m); err != nil {
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return err
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} else if string(username) != expectedUsername {
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return fmt.Errorf("%w expected(%x) actual(%x)", errMismatchUsername, expectedUsername, string(username))
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}
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return nil
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}
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