mirror of https://github.com/jetkvm/kvm.git
135 lines
3.6 KiB
Go
135 lines
3.6 KiB
Go
// SPDX-FileCopyrightText: 2023 The Pion community <https://pion.ly>
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// SPDX-License-Identifier: MIT
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package server
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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/v3"
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"github.com/pion/turn/v4/internal/proto"
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)
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const (
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// See: https://tools.ietf.org/html/rfc5766#section-6.2 defines 3600 seconds recommendation.
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maximumAllocationLifetime = time.Hour
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)
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func buildAndSend(conn net.PacketConn, dst net.Addr, attrs ...stun.Setter) error {
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msg, err := stun.Build(attrs...)
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if err != nil {
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return err
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}
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_, err = conn.WriteTo(msg.Raw, dst)
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if errors.Is(err, net.ErrClosed) {
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return nil
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}
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return err
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}
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// Send a STUN packet and return the original error to the caller.
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func buildAndSendErr(conn net.PacketConn, dst net.Addr, err error, attrs ...stun.Setter) error {
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if sendErr := buildAndSend(conn, dst, attrs...); sendErr != nil {
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err = fmt.Errorf("%w %v %v", errFailedToSendError, sendErr, err) //nolint:errorlint
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}
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return err
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}
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func buildMsg(
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transactionID [stun.TransactionIDSize]byte,
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msgType stun.MessageType,
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additional ...stun.Setter,
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) []stun.Setter {
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return append([]stun.Setter{&stun.Message{TransactionID: transactionID}, msgType}, additional...)
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}
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func authenticateRequest(req Request, stunMsg *stun.Message, callingMethod stun.Method) (
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stun.MessageIntegrity,
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bool,
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error,
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) {
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respondWithNonce := func(responseCode stun.ErrorCode) (stun.MessageIntegrity, bool, error) {
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nonce, err := req.NonceHash.Generate()
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if err != nil {
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return nil, false, err
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}
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return nil, false, buildAndSend(req.Conn, req.SrcAddr, buildMsg(stunMsg.TransactionID,
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stun.NewType(callingMethod, stun.ClassErrorResponse),
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&stun.ErrorCodeAttribute{Code: responseCode},
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stun.NewNonce(nonce),
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stun.NewRealm(req.Realm),
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)...)
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}
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if !stunMsg.Contains(stun.AttrMessageIntegrity) {
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return respondWithNonce(stun.CodeUnauthorized)
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}
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nonceAttr := &stun.Nonce{}
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usernameAttr := &stun.Username{}
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realmAttr := &stun.Realm{}
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badRequestMsg := buildMsg(
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stunMsg.TransactionID,
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stun.NewType(callingMethod, stun.ClassErrorResponse),
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&stun.ErrorCodeAttribute{Code: stun.CodeBadRequest},
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)
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// No Auth handler is set, server is running in STUN only mode
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// Respond with 400 so clients don't retry.
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if req.AuthHandler == nil {
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sendErr := buildAndSend(req.Conn, req.SrcAddr, badRequestMsg...)
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return nil, false, sendErr
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}
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if err := nonceAttr.GetFrom(stunMsg); err != nil {
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return nil, false, buildAndSendErr(req.Conn, req.SrcAddr, err, badRequestMsg...)
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}
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// Assert Nonce is signed and is not expired.
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if err := req.NonceHash.Validate(nonceAttr.String()); err != nil {
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return respondWithNonce(stun.CodeStaleNonce)
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}
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if err := realmAttr.GetFrom(stunMsg); err != nil {
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return nil, false, buildAndSendErr(req.Conn, req.SrcAddr, err, badRequestMsg...)
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} else if err := usernameAttr.GetFrom(stunMsg); err != nil {
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return nil, false, buildAndSendErr(req.Conn, req.SrcAddr, err, badRequestMsg...)
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}
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ourKey, ok := req.AuthHandler(usernameAttr.String(), realmAttr.String(), req.SrcAddr)
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if !ok {
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return nil, false, buildAndSendErr(
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req.Conn,
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req.SrcAddr,
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fmt.Errorf("%w %s", errNoSuchUser, usernameAttr.String()),
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badRequestMsg...,
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)
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}
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if err := stun.MessageIntegrity(ourKey).Check(stunMsg); err != nil {
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return nil, false, buildAndSendErr(req.Conn, req.SrcAddr, err, badRequestMsg...)
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}
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return stun.MessageIntegrity(ourKey), true, nil
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}
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func allocationLifeTime(m *stun.Message) time.Duration {
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lifetimeDuration := proto.DefaultLifetime
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var lifetime proto.Lifetime
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if err := lifetime.GetFrom(m); err == nil {
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if lifetime.Duration < maximumAllocationLifetime {
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lifetimeDuration = lifetime.Duration
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}
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}
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return lifetimeDuration
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}
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