Add domain sniffer

common/sniff/http.go

@@ -0,0 +1,19 @@
+package sniff
+
+import (
+	std_bufio "bufio"
+	"context"
+	"io"
+
+	"github.com/sagernet/sing-box/adapter"
+	C "github.com/sagernet/sing-box/constant"
+	"github.com/sagernet/sing/protocol/http"
+)
+
+func HTTPHost(ctx context.Context, reader io.Reader) (*adapter.InboundContext, error) {
+	request, err := http.ReadRequest(std_bufio.NewReader(reader))
+	if err != nil {
+		return nil, err
+	}
+	return &adapter.InboundContext{Protocol: C.ProtocolHTTP, Domain: request.Host}, nil
+}