添加新的网口标识

cmd/internal/peer/client.go

@@ -6,16 +6,19 @@ import (
 	"os"
 	"path/filepath"
 	"sync/atomic"
+	"syscall"
 
 	"omnisocketgo/cmd/internal/latencylog"
 	"omnisocketgo/cmd/internal/protocol"
 	"omnisocketgo/cmd/internal/transport"
 )
 
-var dialServer = net.Dial
+var dialServer = dialServerWithOptions
 
 type clientOptions struct {
-	logger latencylog.Logger
+	logger     latencylog.Logger
+	bindIP     string
+	bindDevice string
 }
 
 // Option 用于配置 Client 的可选行为，例如时延日志。
@@ -28,6 +31,20 @@ func WithLogger(logger latencylog.Logger) Option {
 	}
 }
 
+// WithBindIP 指定拨号时使用的本地源 IP。
+func WithBindIP(ip string) Option {
+	return func(options *clientOptions) {
+		options.bindIP = ip
+	}
+}
+
+// WithBindDevice 指定拨号时绑定的 Linux 网卡名，例如 eth0 或 wwan0。
+func WithBindDevice(device string) Option {
+	return func(options *clientOptions) {
+		options.bindDevice = device
+	}
+}
+
 // Client 表示一个已经连接到 server 的 peer。
 type Client struct {
 	id     string
@@ -49,7 +66,7 @@ func Dial(serverAddr, peerID string, opts ...Option) (*Client, error) {
 		options.logger = latencylog.NoopLogger{}
 	}
 
-	rawConn, err := dialServer("tcp", serverAddr) //使用 net.Dial 连接到 serverAddr 指定的 TCP 地址，返回一个 net.Conn。
+	rawConn, err := dialServer(serverAddr, options)
 	if err != nil {
 		return nil, fmt.Errorf("peer: dial server: %w", err)
 	}
@@ -177,3 +194,42 @@ func (c *Client) Close() error {
 func (c *Client) nextMessageID() uint64 {
 	return atomic.AddUint64(&c.nextID, 1)
 }
+
+func dialServerWithOptions(serverAddr string, options clientOptions) (net.Conn, error) {
+	dialer, err := buildDialer(options)
+	if err != nil {
+		return nil, err
+	}
+
+	return dialer.Dial("tcp", serverAddr)
+}
+
+func buildDialer(options clientOptions) (*net.Dialer, error) {
+	dialer := &net.Dialer{}
+
+	if options.bindIP != "" {
+		ip := net.ParseIP(options.bindIP)
+		if ip == nil {
+			return nil, fmt.Errorf("peer: invalid bind ip %q", options.bindIP)
+		}
+		dialer.LocalAddr = &net.TCPAddr{IP: ip}
+	}
+
+	if options.bindDevice != "" {
+		device := options.bindDevice
+		dialer.Control = func(_, _ string, rawConn syscall.RawConn) error {
+			var bindErr error
+			if err := rawConn.Control(func(fd uintptr) {
+				bindErr = syscall.BindToDevice(int(fd), device)
+			}); err != nil {
+				return err
+			}
+			if bindErr != nil {
+				return fmt.Errorf("peer: bind device %s: %w", device, bindErr)
+			}
+			return nil
+		}
+	}
+
+	return dialer, nil
+}