feat: 握手写完了

examples/bin.rs

@@ -0,0 +1,69 @@
+use rs_tcp::*;
+use std::{
+    collections::{hash_map::Entry, HashMap},
+    io,
+};
+
+fn main() -> io::Result<()> {
+    let mut nic = tun_tap::Iface::without_packet_info("mytun0", tun_tap::Mode::Tun)?;
+    let mut buffer = vec![0; 1500];
+    // 保存所有连接对应的状态
+    let mut connections: HashMap<Quad, Connection> = HashMap::new();
+
+    loop {
+        let nbytes = nic.recv(&mut buffer).unwrap();
+        // 忽略非TCP数据包
+        match etherparse::Ipv4HeaderSlice::from_slice(&buffer) {
+            Ok(iph) => {
+                let src = iph.source_addr();
+                let dst = iph.destination_addr();
+                let proto = iph.protocol();
+                if proto != etherparse::IpNumber(0x06) {
+                    continue;
+                }
+                match etherparse::TcpHeaderSlice::from_slice(&buffer[iph.slice().len()..nbytes]) {
+                    Ok(tcph) => {
+                        let payload_offset = iph.slice().len() + tcph.slice().len();
+                        let mut payload = &buffer[payload_offset..nbytes];
+                        
+                        let recv_quad = Quad {
+                            src: (src, tcph.source_port()),
+                            dst: (dst, tcph.destination_port()),
+                        };
+                        // 这里我们需要处理接收到的Tcp数据包
+                        match connections.entry(recv_quad) {
+                            Entry::Occupied(mut occupied_entry) => {
+                                // 已经存在的连接
+                                occupied_entry.get_mut().on_packet(iph, tcph, &payload);
+                            },
+                            Entry::Vacant(vacant_entry) => {
+                                eprintln!(
+                                    "{}:{} -> {}:{} first handpacket syn: {}, seq: {}",
+                                    src,
+                                    tcph.source_port(),
+                                    dst,
+                                    tcph.destination_port(),
+                                    tcph.syn(),
+                                    tcph.sequence_number()
+                                );
+                                // 第一次接受的包
+                                if let Some(c) = Connection::accept(&mut nic, iph, tcph)?{
+                                    vacant_entry.insert(c);
+                                }
+                            },
+                        }
+                    }
+                    Err(e) => {
+                        // 这不是一个TCP包 但是协议是TCP
+                        eprintln!("ignoring weird packet: {:?}", e)
+                    }
+                }
+            }
+            Err(_) => {
+                // 非IP标准包 忽略
+                continue;
+            }
+        };
+    }
+    Ok(())
+}