Struct BackendConn 

pub struct BackendConn {
    pub user_id: AtomicU32,
    pub client_ver: u16,
    /* private fields */
}

后端连接

Fields

user_id: AtomicU32

client_ver: u16

Implementations

impl BackendConn

pub async fn request_for_test( &self, cmd_id: u16, body: Vec<u8>, ) -> Result<NNFrame>

Test-only transport probe used by the duplex mock-backend canary.

This deliberately has a different name from the production primitive, and is absent unless test-util is explicitly enabled.

impl BackendConn

pub fn pending_request_count_for_test(&self) -> usize

impl BackendConn

pub const CONNECT_TIMEOUT: Duration

连接 TCP 的超时时间。

Linux 默认 tcp_syn_retries=6 时 TcpStream::connect 等到 ETIMEDOUT 需要约 127 秒——用户启动 opend 时如果选到一个不通的 IP 就卡 2 分钟后 才报错 offline mode（某位 Rocky Linux 用户踩过）。加 10s 超时快速失败， 让上层（bridge.rs 的 connect 循环）有机会 fallback 到下一个候选 IP。

pub const CLIENT_VER_FTGTW: u16 = 1031

Backend 侧可识别的 Rust OpenD 固定客户端版本号。

C++ 同时把 AppConfig::GetClientVersion() 写入 protocol header 与 ReqEncryptData.client_ex_ver；为便于后台识别，Rust OpenD 于 2026-07-14 将识别版本提升为 1031。该身份在首次建连和鉴权请求发出前必须已知， 不能从服务端动态配置取得；尚未识别 1031 的 backend 环境可能拒绝登录。 若后台重新分配版本， 只更新本常量，并由契约测试保证所有 wire/HTTP 出口同步变化。 Ref: f3c/FTNet/Src/ftnet/channel/impl/protocol_header.cpp:25-32 and f3c/FTlogin/Src/ftlogin/login/logger.cpp:304-310.

pub async fn connect( addr: &str, push_callback: PushCallback, protocol_identity: BackendProtocolIdentity, ) -> Result<Self>

连接到后端服务器（带 10s 超时）

pub async fn connect_race( addrs: &[String], push_callback: PushCallback, protocol_identity: BackendProtocolIdentity, ) -> Result<(Self, String)>

并发连接多个候选地址，谁先通用谁（对齐 C++ connector.cpp:175-189 ConnectStrategyAddr 的 concurrency_ip 语义）。

• 每个候选独立带 CONNECT_TIMEOUT（10s）超时
• 第一个 Ok(stream) 胜出，其余 pending task drop 时会关闭半连接
• 全部失败返回最后一个错误

返回 (BackendConn, winner_addr)，调用方用 winner_addr 做登录协议里的 host_ip/host_port 字段。

pub fn from_duplex( stream: DuplexStream, push_callback: PushCallback, protocol_identity: BackendProtocolIdentity, ) -> Self

v1.4.70 D1: test-only 从 tokio::io::DuplexStream 构造 BackendConn

用于 integration tests（crates/futu-gateway/tests/common/mock_backend.rs） 替代真 TcpStream。生产路径通过 connect() → from_stream() 不变。

pub const fn protocol_identity(&self) -> BackendProtocolIdentity

pub fn set_session_key(&self, key: Vec<u8>)

设置 session key（登录成功后调用）。接受变长字节，16/24/32 分别对应 AES-128/192/256。对齐 C++ Logger::session_key_ 是 std::string， 长度取决于服务端下发的 RspEncryptData.session_key 字段原始长度。

pub fn set_sec_data(&self, val: u32)

设置 sec_data 初始值（登录成功后调用）

pub fn apply_login_sec_data(&self, val: Option<u32>)

应用登录响应里的 sec_data。

C++ 只有在 RspEncryptData.has_sec_data() 时更新 secure_num_； 字段缺失时保留当前计数，避免 reconnect/login 响应裁剪时把安全数回退。

Ref: f3c/FTlogin/Src/ftlogin/login/logger.cpp:553-555.

pub fn set_client_ip(&self, ip: String)

设置登录响应里的客户端外网 IP。

pub fn client_ip(&self) -> String

读取登录响应里的客户端外网 IP。

pub fn connection_generation(&self) -> u64

Immutable identity of this transport instance, included with every backend push so consumers can reject delivery from a retired route.

pub fn pause_writer_admission_for_test(&self) -> LifecyclePauseHook

pub fn is_connected(&self) -> bool

pub fn subscribe_connection_state(&self) -> Receiver<bool>

Subscribe to low-level connection liveness changes.

C++ FTLogin publishes a connection-closed event immediately (GTWCmdAndPushReply::OMEvProc_ConnClosed) and lets the gateway enter reconnecting state without waiting for a later business request. Rust uses this watch channel to wake the reconnect monitor as soon as the recv/send task marks the TCP channel disconnected.

pub fn mark_disconnected_for_reconnect(&self, reason: &'static str)

Mark this connection disconnected so owner-side reconnect loops stop routing business requests through a stale session.

Used when a higher-level channel event invalidates the session semantics even if the TCP socket has not closed yet. C++ channel state transitions publish disconnect/re-establish events; Rust exposes the same liveness edge through the existing connection-state watch channel.

Trait Implementations

impl Drop for BackendConn

fn drop(&mut self)

Executes the destructor for this type.

fn pin_drop(self: Pin<&mut Self>)

🔬This is a nightly-only experimental API. (pin_ergonomics)

Execute the destructor for this type, but different to Drop::drop, it requires self to be pinned.