Feat 使 TCP 发起 Connect 可用

Samuka007 · 2024 年11 月 20 日 09:26

在 master 下，以及现在的 feat-network-rebuild ，是不支持发起 tcp connect 的。开发跟踪于此。

Samuka007 · 2024 年11 月 20 日 11:44

在 smoltcp 的示例中，socket只需要简单的 connect，然后即可轮询是否建立连接：

smoltcp-rs/smoltcp/blob/9027825c16c9c3fbadb7663e56d64b590fc95d5a/examples/httpclient.rs#L85-L87


      
          socket
              .connect(cx, (address, url.port().unwrap_or(80)), local_port)
              .unwrap();

=>

github.com

smoltcp-rs/smoltcp/blob/9027825c16c9c3fbadb7663e56d64b590fc95d5a/examples/httpclient.rs#L90-L101


      
          State::Request if socket.may_send() => {
              debug!("sending request");
              let http_get = "GET ".to_owned() + url.path() + " HTTP/1.1\r\n";
              socket.send_slice(http_get.as_ref()).expect("cannot send");
              let http_host = "Host: ".to_owned() + url.host_str().unwrap() + "\r\n";
              socket.send_slice(http_host.as_ref()).expect("cannot send");
              socket
                  .send_slice(b"Connection: close\r\n")
                  .expect("cannot send");
              socket.send_slice(b"\r\n").expect("cannot send");
              State::Response
          }

然而在系统内部实现中并不行，现试图使用 tun/tap 网卡在linux上测试connect特性。

整个状态机的代码见：

github.com

smoltcp-rs/smoltcp/blob/9027825c16c9c3fbadb7663e56d64b590fc95d5a/examples/httpclient.rs#L81-L116


      
          state = match state {
              State::Connect if !socket.is_active() => {
                  debug!("connecting");
                  let local_port = 49152 + rand::random::<u16>() % 16384;
                  socket
                      .connect(cx, (address, url.port().unwrap_or(80)), local_port)
                      .unwrap();
                  State::Request
              }
              State::Request if socket.may_send() => {
                  debug!("sending request");
                  let http_get = "GET ".to_owned() + url.path() + " HTTP/1.1\r\n";
                  socket.send_slice(http_get.as_ref()).expect("cannot send");
                  let http_host = "Host: ".to_owned() + url.host_str().unwrap() + "\r\n";
                  socket.send_slice(http_host.as_ref()).expect("cannot send");
                  socket
                      .send_slice(b"Connection: close\r\n")
                      .expect("cannot send");
                  socket.send_slice(b"\r\n").expect("cannot send");
                  State::Response

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longjin · 2024 年11 月 20 日 12:45

为啥？不是有connect那个系统调用了吗

Samuka007 · 2024 年11 月 20 日 13:34

坏了，用不了（）