518 lines
18 KiB
Go
518 lines
18 KiB
Go
package phone
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import (
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"bytes"
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"context"
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"crypto/sha256"
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"errors"
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"strconv"
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"strings"
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"time"
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"github.com/iamxvbaba/td/clock"
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"telesrv/internal/domain"
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)
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// 客户端可识别的业务错误；rpc 层映射为对应 RPC_ERROR（CALL_* 等）。
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var (
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ErrPeerInvalid = errors.New("phone: call peer invalid")
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ErrAlreadyAccepted = errors.New("phone: call already accepted")
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ErrAlreadyDeclined = errors.New("phone: call already declined")
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ErrOccupyFailed = errors.New("phone: too many active calls")
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ErrProtocolLayerInvalid = errors.New("phone: protocol layer invalid")
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ErrProtocolCompatLayerInvalid = errors.New("phone: protocol compat layer invalid")
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ErrProtocolFlagsInvalid = errors.New("phone: protocol flags invalid")
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// ErrGAHashMismatch：confirmCall 揭示的 g_a 与 requestCall 承诺的 SHA256 不符。
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// 服务端同时把通话强制置为 discarded(disconnect)，防止攻击者卡死状态机。
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ErrGAHashMismatch = errors.New("phone: g_a does not match committed hash")
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)
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// minSupportedLayer 是 libtgvoip/tgcalls 的最低协议层（TDesktop kMinLayer、
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// DrKLO VoIPService.CALL_MIN_LAYER 均为 65）。
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const minSupportedLayer = 65
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const (
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gaHashSize = sha256.Size // 32
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dhPubSize = 256 // g_a / g_b 都是 2048-bit
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)
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// Config 是通话服务的运行参数。
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type Config struct {
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// RingTimeout 是服务端兜底超时（与下发给客户端的 callRingTimeoutMs 同源，默认 90s）。
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RingTimeout time.Duration
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// TombstoneTTL 是终态 tombstone 保留期（吸收双方同时挂断/晚到 RPC 的幂等窗口）。
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TombstoneTTL time.Duration
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// MaxActivePerUser 是单用户并发非终态通话上限（防呼叫轰炸自锁）。
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MaxActivePerUser int
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// MaxRegistryEntries 是进程内 registry 的硬上限。达到上限时拒绝新通话，
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// 不驱逐可能仍在进行的 Confirmed 通话。
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MaxRegistryEntries int
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// SignalingRatePerSecond 是单通话每秒信令转发上限；超限静默丢弃（不破坏客户端状态机）。
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SignalingRatePerSecond int
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}
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func (c Config) withDefaults() Config {
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if c.RingTimeout <= 0 {
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c.RingTimeout = 90 * time.Second
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}
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if c.TombstoneTTL <= 0 {
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c.TombstoneTTL = 60 * time.Second
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}
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if c.MaxActivePerUser <= 0 {
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c.MaxActivePerUser = 4
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}
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if c.MaxRegistryEntries <= 0 {
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c.MaxRegistryEntries = 10_000
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}
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if c.SignalingRatePerSecond <= 0 {
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c.SignalingRatePerSecond = 50
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}
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return c
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}
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// Service 实现私聊通话信令状态机。所有方法返回的 domain.PhoneCall 都是当时快照。
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type Service struct {
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cfg Config
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clk clock.Clock
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reg *registry
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}
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// Option 配置 Service。
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type Option func(*Service)
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// WithClock 注入测试时钟。
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func WithClock(clk clock.Clock) Option {
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return func(s *Service) { s.clk = clk }
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}
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// NewService 创建通话服务。
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func NewService(cfg Config, opts ...Option) *Service {
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s := &Service{cfg: cfg.withDefaults(), clk: clock.System, reg: newRegistry()}
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for _, opt := range opts {
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opt(s)
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}
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return s
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}
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// RequestCall 受理主叫请求：校验协议与配额、(callerID, randomID) 幂等去重、建档。
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// 隐私/拉黑/目标用户合法性由 rpc 层先行校验。
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func (s *Service) RequestCall(ctx context.Context, callerID int64, in domain.PhoneCallRequest) (domain.PhoneCall, error) {
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if err := validateProtocol(in.Protocol); err != nil {
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return domain.PhoneCall{}, err
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}
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if len(in.GAHash) != gaHashSize {
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return domain.PhoneCall{}, ErrProtocolFlagsInvalid
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}
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now := s.clk.Now()
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nowUnix := now.Unix()
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s.reg.mu.Lock()
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defer s.reg.mu.Unlock()
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s.reg.sweepTombstonesLocked(nowUnix, int64(s.cfg.TombstoneTTL/time.Second))
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// 幂等：同一 (callerID, randomID) 的未终结通话直接返回快照，吸收客户端重试。
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key := randomKey{callerID: callerID, randomID: in.RandomID}
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if id, ok := s.reg.byRandom[key]; ok {
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if e, ok := s.reg.byID[id]; ok && !e.call.Terminal() {
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return e.call, nil
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}
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}
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if len(s.reg.byID) >= s.cfg.MaxRegistryEntries {
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return domain.PhoneCall{}, ErrOccupyFailed
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}
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if s.reg.active[callerID] >= s.cfg.MaxActivePerUser {
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return domain.PhoneCall{}, ErrOccupyFailed
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}
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id, err := s.reg.newIDLocked()
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if err != nil {
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return domain.PhoneCall{}, err
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}
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accessHash, err := randomPositiveInt64()
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if err != nil {
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return domain.PhoneCall{}, err
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}
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call := domain.PhoneCall{
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ID: id,
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AccessHash: accessHash,
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AdminID: callerID,
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ParticipantID: in.CalleeID,
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Video: in.Video,
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State: domain.PhoneCallStateRequested,
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Date: int(nowUnix),
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GAHash: append([]byte(nil), in.GAHash...),
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CallerProtocol: in.Protocol,
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Protocol: in.Protocol,
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RandomID: in.RandomID,
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CallerDevice: in.CallerDevice,
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PrivacyP2P: in.PrivacyP2P,
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Connections: append([]domain.PhoneCallConnection(nil), in.Connections...),
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}
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s.reg.byID[id] = &entry{call: call}
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s.reg.byRandom[key] = id
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s.reg.active[callerID]++
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return call, nil
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}
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// ReceivedCall 标记被叫设备已收到来电。首次（Requested→Ringing）返回 transitioned=true，
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// 其余状态幂等成功（多设备各自上报、晚到无害）。
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func (s *Service) ReceivedCall(ctx context.Context, userID, callID, accessHash int64) (domain.PhoneCall, bool, error) {
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s.reg.mu.Lock()
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defer s.reg.mu.Unlock()
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e, err := s.lookupLocked(callID, accessHash)
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if err != nil {
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return domain.PhoneCall{}, false, err
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}
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if userID != e.call.ParticipantID {
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// receivedCall 只能由被叫上报。
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return domain.PhoneCall{}, false, ErrPeerInvalid
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}
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if e.call.State == domain.PhoneCallStateRequested {
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e.call.State = domain.PhoneCallStateRinging
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e.call.ReceiveDate = int(s.clk.Now().Unix())
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return e.call, true, nil
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}
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return e.call, false, nil
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}
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// AcceptCall 受理被叫接听。多设备并发竞争由 registry 锁串行化：首个完成迁移者赢，
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// 后到者收 ErrAlreadyAccepted（其 UI 自行收场）。
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func (s *Service) AcceptCall(ctx context.Context, userID, callID, accessHash int64, gb []byte, proto domain.PhoneCallProtocol, device domain.SessionRef) (domain.PhoneCall, error) {
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if err := validateProtocol(proto); err != nil {
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return domain.PhoneCall{}, err
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}
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if len(gb) != dhPubSize || allZero(gb) {
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return domain.PhoneCall{}, ErrProtocolFlagsInvalid
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}
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s.reg.mu.Lock()
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defer s.reg.mu.Unlock()
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e, err := s.lookupLocked(callID, accessHash)
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if err != nil {
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return domain.PhoneCall{}, err
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}
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if userID != e.call.ParticipantID {
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return domain.PhoneCall{}, ErrPeerInvalid
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}
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switch e.call.State {
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case domain.PhoneCallStateRequested, domain.PhoneCallStateRinging:
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// 合法路径；未 receivedCall 直接 accept 也允许。
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case domain.PhoneCallStateAccepted, domain.PhoneCallStateConfirmed:
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return domain.PhoneCall{}, ErrAlreadyAccepted
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case domain.PhoneCallStateDiscarded:
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return domain.PhoneCall{}, ErrAlreadyDeclined
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}
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negotiated, err := negotiateProtocol(e.call.CallerProtocol, proto)
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if err != nil {
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return domain.PhoneCall{}, err
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}
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e.call.GB = append([]byte(nil), gb...)
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e.call.CalleeProtocol = proto
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e.call.Protocol = negotiated
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e.call.CalleeDevice = device
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e.call.State = domain.PhoneCallStateAccepted
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// 不解除超时：同一只表继续走，主叫永不 confirm 时由兜底超时收尾。
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return e.call, nil
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}
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// ConfirmCall 受理主叫确认：核验 SHA256(g_a) 与承诺一致后进入 Confirmed。
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// 核验失败时通话被强制置为 discarded(disconnect)，返回 (终态快照, true, ErrGAHashMismatch)，
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// 调用方须把终态推送给双方。
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func (s *Service) ConfirmCall(ctx context.Context, userID, callID, accessHash int64, ga []byte, keyFingerprint int64, proto domain.PhoneCallProtocol) (domain.PhoneCall, bool, error) {
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s.reg.mu.Lock()
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defer s.reg.mu.Unlock()
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e, err := s.lookupLocked(callID, accessHash)
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if err != nil {
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return domain.PhoneCall{}, false, err
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}
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if userID != e.call.AdminID {
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return domain.PhoneCall{}, false, ErrPeerInvalid
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}
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switch e.call.State {
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case domain.PhoneCallStateAccepted:
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case domain.PhoneCallStateConfirmed:
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return domain.PhoneCall{}, false, ErrAlreadyAccepted
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case domain.PhoneCallStateDiscarded:
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return domain.PhoneCall{}, false, ErrAlreadyDeclined
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default: // Requested / Ringing：被叫尚未 accept，confirm 非法。
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return domain.PhoneCall{}, false, ErrPeerInvalid
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}
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// confirmCall 携带的第三份 protocol 仅校验合法性，不改 accept 时的协商结果
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//（官方语义：协商在 accept 完成，confirm 的 protocol 是回显）。
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if err := validateProtocol(proto); err != nil {
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return domain.PhoneCall{}, false, err
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}
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if len(ga) != dhPubSize || sha256Mismatch(ga, e.call.GAHash) {
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now := int(s.clk.Now().Unix())
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s.reg.markDiscardedLocked(e, domain.PhoneCallDiscardReasonDisconnect, 0, now)
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return e.call, true, ErrGAHashMismatch
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}
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e.call.GA = append([]byte(nil), ga...)
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e.call.KeyFingerprint = keyFingerprint
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e.call.StartDate = int(s.clk.Now().Unix())
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// p2p_allowed = 双方 protocol 都允许 P2P ∧ phone_p2p 隐私双向放行（P3 起
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// PrivacyP2P 由 rpc 层算定，强制 relay 时也走它置 false）。false 时 tgcalls
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// 只用 relay candidates——前提是 connections 里有可用 TURN。
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e.call.P2PAllowed = e.call.CallerProtocol.UDPP2P && e.call.CalleeProtocol.UDPP2P && e.call.PrivacyP2P
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e.call.State = domain.PhoneCallStateConfirmed
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return e.call, false, nil
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}
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// DiscardCall 挂断：任意非终态可达，幂等。already=true 表示通话此前已是终态
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// （双方同时挂断：先到者定 reason，后到者拿快照）。
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func (s *Service) DiscardCall(ctx context.Context, userID, callID, accessHash int64, reason domain.PhoneCallDiscardReason, duration int) (domain.PhoneCall, bool, error) {
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return s.DiscardCallWithSlug(ctx, userID, callID, accessHash, reason, "", duration)
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}
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func (s *Service) DiscardCallWithSlug(ctx context.Context, userID, callID, accessHash int64, reason domain.PhoneCallDiscardReason, reasonSlug string, duration int) (domain.PhoneCall, bool, error) {
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s.reg.mu.Lock()
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defer s.reg.mu.Unlock()
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e, err := s.lookupLocked(callID, accessHash)
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if err != nil {
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return domain.PhoneCall{}, false, err
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}
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if !e.call.HasParticipant(userID) {
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return domain.PhoneCall{}, false, ErrPeerInvalid
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}
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if e.call.Terminal() {
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return e.call, true, nil
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}
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if reason == "" {
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reason = domain.PhoneCallDiscardReasonHangup
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}
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if reason != domain.PhoneCallDiscardReasonMigrateConference {
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reasonSlug = ""
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}
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// duration 只在通话真正建立（Confirmed）后才认，防止客户端把振铃时长报成通话时长。
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if e.call.StartDate == 0 || duration < 0 {
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duration = 0
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}
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s.reg.markDiscardedWithSlugLocked(e, reason, reasonSlug, duration, int(s.clk.Now().Unix()))
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return e.call, false, nil
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}
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// ExpireDue 把超时的非终态通话迁入终态并返回快照（调用方负责推送与落历史）：
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// Requested/Ringing 超时 → missed（即「未接来电」来源）；Accepted 悬挂（主叫
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// 永不 confirm）→ disconnect。Confirmed 通话没有服务端时长上限，不在此回收。
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// 顺带做 tombstone GC。
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func (s *Service) ExpireDue(ctx context.Context, now time.Time) []domain.PhoneCall {
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nowUnix := now.Unix()
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ringSec := int64(s.cfg.RingTimeout / time.Second)
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s.reg.mu.Lock()
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defer s.reg.mu.Unlock()
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var expired []domain.PhoneCall
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for _, e := range s.reg.byID {
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if e.call.Terminal() || e.call.State == domain.PhoneCallStateConfirmed {
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continue
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}
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if nowUnix-int64(e.call.Date) <= ringSec {
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continue
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}
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reason := domain.PhoneCallDiscardReasonMissed
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if e.call.State == domain.PhoneCallStateAccepted {
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reason = domain.PhoneCallDiscardReasonDisconnect
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}
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s.reg.markDiscardedLocked(e, reason, 0, int(nowUnix))
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expired = append(expired, e.call)
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}
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s.reg.sweepTombstonesLocked(nowUnix, int64(s.cfg.TombstoneTTL/time.Second))
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return expired
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}
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// Signal 校验并串行转发一条信令。forward 在该通话专属的信令顺序锁内执行
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// （保证转发顺序与受理顺序一致），状态锁不跨 forward 持有。peerDevice 是对端
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// 受理设备锚点（可能为零值/已失效），仅作定向推送 fast-path 提示。
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// drop=true 表示按契约静默吞掉（tombstone 尾包 / 超过速率上限），调用方应返回成功。
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func (s *Service) Signal(ctx context.Context, userID, callID, accessHash int64, forward func(peerUserID int64, peerDevice domain.SessionRef)) (drop bool, err error) {
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s.reg.mu.Lock()
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e, lookupErr := s.lookupLocked(callID, accessHash)
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if lookupErr != nil {
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s.reg.mu.Unlock()
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return false, lookupErr
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}
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if !e.call.HasParticipant(userID) {
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s.reg.mu.Unlock()
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return false, ErrPeerInvalid
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}
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state := e.call.State
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peer := e.call.PeerOf(userID)
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peerDevice := e.call.CalleeDevice
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if peer == e.call.AdminID {
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peerDevice = e.call.CallerDevice
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}
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s.reg.mu.Unlock()
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switch state {
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case domain.PhoneCallStateAccepted, domain.PhoneCallStateConfirmed:
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// 可转发。DrKLO 在 confirm 前后都可能发信令，Accepted 即放行。
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case domain.PhoneCallStateDiscarded:
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// 挂断瞬间的尾包：返回错误会让 TDesktop 把正常挂断渲染成「通话失败」
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//（其 sendSignalingData 的 .done 校验 mtpIsTrue），静默丢弃。
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return true, nil
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default:
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return false, ErrPeerInvalid
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}
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e.sigMu.Lock()
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defer e.sigMu.Unlock()
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nowSec := s.clk.Now().Unix()
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if e.sigWindowSec != nowSec {
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e.sigWindowSec = nowSec
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e.sigCount = 0
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}
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if e.sigCount >= s.cfg.SignalingRatePerSecond {
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return true, nil
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}
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e.sigCount++
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forward(peer, peerDevice)
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return false, nil
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}
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// Lookup 返回通话快照（rpc 层宽容校验 setCallRating/saveCallDebug 等晚到请求用）。
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func (s *Service) Lookup(ctx context.Context, callID, accessHash int64) (domain.PhoneCall, bool) {
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s.reg.mu.Lock()
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defer s.reg.mu.Unlock()
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e, err := s.lookupLocked(callID, accessHash)
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if err != nil {
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return domain.PhoneCall{}, false
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}
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return e.call, true
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}
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func (s *Service) lookupLocked(callID, accessHash int64) (*entry, error) {
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e, ok := s.reg.byID[callID]
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if !ok || e.call.AccessHash != accessHash {
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return nil, ErrPeerInvalid
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}
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return e, nil
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}
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func validateProtocol(p domain.PhoneCallProtocol) error {
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if p.MinLayer > p.MaxLayer {
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return ErrProtocolLayerInvalid
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}
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if p.MaxLayer < minSupportedLayer {
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return ErrProtocolCompatLayerInvalid
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}
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if !p.UDPP2P && !p.UDPReflector {
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return ErrProtocolFlagsInvalid
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}
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if len(p.LibraryVersions) == 0 {
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return ErrProtocolFlagsInvalid
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}
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return nil
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}
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// negotiateProtocol 在 accept 时合并双方 protocol（官方语义：服务端只回「最优」单值
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// library version）。版本无交集时透传被叫列表（被叫是先实例化 tgcalls 的一方，
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// 主叫侧有 kDefaultVersion 兜底）——绝不因版本差异拒绝通话。
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func negotiateProtocol(caller, callee domain.PhoneCallProtocol) (domain.PhoneCallProtocol, error) {
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out := domain.PhoneCallProtocol{
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||
UDPP2P: caller.UDPP2P && callee.UDPP2P,
|
||
UDPReflector: caller.UDPReflector || callee.UDPReflector,
|
||
MinLayer: maxInt(caller.MinLayer, callee.MinLayer),
|
||
MaxLayer: minInt(caller.MaxLayer, callee.MaxLayer),
|
||
}
|
||
if out.MinLayer > out.MaxLayer {
|
||
return domain.PhoneCallProtocol{}, ErrProtocolCompatLayerInvalid
|
||
}
|
||
if best, ok := bestCommonVersion(caller.LibraryVersions, callee.LibraryVersions); ok {
|
||
out.LibraryVersions = []string{best}
|
||
} else {
|
||
out.LibraryVersions = append([]string(nil), callee.LibraryVersions...)
|
||
}
|
||
return out, nil
|
||
}
|
||
|
||
// preferredVersions 是交集命中时的优先选择序（读客户端源码定下的硬约束）：
|
||
// - "9.0.0"=InstanceV2Impl+V2 消息级信令，TDesktop 与 DrKLO 注册表都有，最稳；
|
||
// - ⚠ 绝不能选 "10.0.0"/"11.0.0"/"12.0.0"/"13.0.0" 当 [0]：DrKLO 的视频可用性
|
||
// 判断是 `"2.7.7".compareTo(versions[0]) <= 0` 的**字符串字典序**比较
|
||
// （VoIPService.java:3464），"1x.0.0" 字典序小于 "2.7.7" 会让 Android 直接
|
||
// 销毁摄像头采集（视频通话黑屏）；"12/13" 还是 V3 SCTP-over-signaling，
|
||
// 对服务端信令限速不友好；
|
||
// - 也绝不能选 "2.7.7"/"5.0.0"/"2.4.4"：legacy 实现依赖我们不下发的
|
||
// reflector endpoints，无路可走。
|
||
var preferredVersions = []string{"9.0.0", "8.0.0", "7.0.0"}
|
||
|
||
// bestCommonVersion 取两侧版本集合交集：优先 preferredVersions 顺位命中，
|
||
// 否则退化为语义化最高者（容忍未来未知版本集）。
|
||
func bestCommonVersion(a, b []string) (string, bool) {
|
||
inB := make(map[string]struct{}, len(b))
|
||
for _, v := range b {
|
||
inB[v] = struct{}{}
|
||
}
|
||
inBoth := make(map[string]struct{}, len(a))
|
||
for _, v := range a {
|
||
if _, ok := inB[v]; ok {
|
||
inBoth[v] = struct{}{}
|
||
}
|
||
}
|
||
for _, v := range preferredVersions {
|
||
if _, ok := inBoth[v]; ok {
|
||
return v, true
|
||
}
|
||
}
|
||
best, found := "", false
|
||
for v := range inBoth {
|
||
if !found || compareVersion(v, best) > 0 {
|
||
best, found = v, true
|
||
}
|
||
}
|
||
return best, found
|
||
}
|
||
|
||
// compareVersion 按点分十进制比较（"9.0.0" < "10.0.0"）；非数字段退化为字符串比较。
|
||
func compareVersion(a, b string) int {
|
||
as, bs := strings.Split(a, "."), strings.Split(b, ".")
|
||
for i := 0; i < len(as) || i < len(bs); i++ {
|
||
var av, bv string
|
||
if i < len(as) {
|
||
av = as[i]
|
||
}
|
||
if i < len(bs) {
|
||
bv = bs[i]
|
||
}
|
||
an, aerr := strconv.Atoi(av)
|
||
bn, berr := strconv.Atoi(bv)
|
||
switch {
|
||
case aerr == nil && berr == nil:
|
||
if an != bn {
|
||
return an - bn
|
||
}
|
||
default:
|
||
if c := strings.Compare(av, bv); c != 0 {
|
||
return c
|
||
}
|
||
}
|
||
}
|
||
return 0
|
||
}
|
||
|
||
func sha256Mismatch(data, want []byte) bool {
|
||
got := sha256.Sum256(data)
|
||
return !bytes.Equal(got[:], want)
|
||
}
|
||
|
||
func allZero(b []byte) bool {
|
||
for _, v := range b {
|
||
if v != 0 {
|
||
return false
|
||
}
|
||
}
|
||
return true
|
||
}
|
||
|
||
func maxInt(a, b int) int {
|
||
if a > b {
|
||
return a
|
||
}
|
||
return b
|
||
}
|
||
|
||
func minInt(a, b int) int {
|
||
if a < b {
|
||
return a
|
||
}
|
||
return b
|
||
}
|